{"id":36671,"date":"2019-10-31T22:13:01","date_gmt":"2019-10-31T19:13:01","guid":{"rendered":"https:\/\/prohoster.info\/blog\/sql-zanimatelnye-zadachki\/"},"modified":"2019-10-31T22:13:01","modified_gmt":"2019-10-31T19:13:01","slug":"sql-zanimatelnye-zadachki","status":"publish","type":"post","link":"https:\/\/prohoster.info\/hu\/blog\/news\/sql-zanimatelnye-zadachki","title":{"rendered":"SQL. \u00c9rdekes feladatok","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Hell\u00f3, Habr!<\/p>\n

M\u00e1r t\u00f6bb mint 3 \u00e9ve tan\u00edtok SQL-t k\u00fcl\u00f6nb\u00f6z\u0151 k\u00e9pz\u0151 k\u00f6zpontokban, \u00e9s az egyik megfigyel\u00e9sem az, hogy a hallgat\u00f3k jobban elsaj\u00e1t\u00edtj\u00e1k \u00e9s \u00e9rtik az SQL-t, ha feladatot adunk nekik, nem pedig csak mes\u00e9l\u00fcnk a lehet\u0151s\u00e9gekr\u0151l \u00e9s a teoretikus alapokr\u00f3l.<\/p>\n

Ebben a cikkben megosztom veletek az \u00e1ltalam hallgat\u00f3knak h\u00e1zi feladatk\u00e9nt adott feladatok list\u00e1j\u00e1t, \u00e9s azokat a brainstormingokat, amelyeken egy\u00fctt dolgozunk, ami m\u00e9ly \u00e9s vil\u00e1gos meg\u00e9rt\u00e9shez vezet az SQL kapcs\u00e1n.<\/p>\n

\"SQL.
\n
\nAz SQL (\u02c8\u025bs\u02c8kju\u02c8\u025bl; angolul structured query language \u2014 \u201estruktur\u00e1lt lek\u00e9rdez\u00e9si nyelv\u201d) egy deklarat\u00edv programoz\u00e1si nyelv, amelyet rel\u00e1ci\u00f3s adatb\u00e1zisban val\u00f3 adatok l\u00e9trehoz\u00e1s\u00e1ra, m\u00f3dos\u00edt\u00e1s\u00e1ra \u00e9s kezel\u00e9s\u00e9re haszn\u00e1lnak, a megfelel\u0151 adatb\u00e1zis-kezel\u0151 rendszer \u00e1ltal ir\u00e1ny\u00edtva. Tov\u00e1bbi r\u00e9szletek\u2026 <\/a><\/noindex><\/p>\n

Az SQL-r\u0151l k\u00fcl\u00f6nb\u00f6z\u0151 forr\u00e1sokb\u00f3l lehet olvasni forr\u00e1sb\u00f3l<\/a><\/noindex>.
\nEz a cikk nem c\u00e9lja, hogy SQL-t tan\u00edtson nektek a null\u00e1r\u00f3l.
\n<\/a><\/noindex>
\nNos, l\u00e1ssuk.<\/p>\n

Haszn\u00e1ljuk a j\u00f3l ismert HR s\u00e9m\u00e1t<\/a><\/noindex> az Oracle-ben a t\u00e1bl\u00e1zataival (Tov\u00e1bbi inform\u00e1ci\u00f3<\/a><\/noindex>):<\/p>\n

\"SQL.
\nMegjegyzem, hogy csak SELECT feladatokat fogunk vizsg\u00e1lni. Itt nincsenek DML \u00e9s DDL feladatok.<\/p>\n

Feladatok<\/h2>\n

\nAdatok korl\u00e1toz\u00e1sa \u00e9s rendez\u00e9se<\/b><\/p>\n

Employees t\u00e1bla. Lista k\u00e9sz\u00edt\u00e9se az \u00f6sszes alkalmazott inform\u00e1ci\u00f3j\u00e1r\u00f3l
\nMegold\u00e1s<\/b><\/p>\n

SELECT * FROM employees\n<\/code><\/pre>\n
Employees t\u00e1bla. K\u00e9rje le az \u00f6sszes munkav\u00e1llal\u00f3 list\u00e1j\u00e1t, akinek a neve ‘David’
\nMegold\u00e1s<\/b><\/p>\n
SELECT *\n  FROM employees\n WHERE first_name = 'David';\n<\/code><\/pre>\n
Employees t\u00e1bla. K\u00e9rje le az \u00f6sszes munkav\u00e1llal\u00f3 list\u00e1j\u00e1t, akinek a job_id \u00e9rt\u00e9ke ‘IT_PROG’
\nMegold\u00e1s<\/b><\/p>\n
SELECT *\n  FROM employees\n WHERE job_id = 'IT_PROG'\n<\/code><\/pre>\n
Employees t\u00e1bla. Minden alkalmazott list\u00e1j\u00e1nak lek\u00e9rdez\u00e9se az 50-es oszt\u00e1lyb\u00f3l (department_id), akikn\u00e9l a fizet\u00e9s (salary) nagyobb mint 4000
\nMegold\u00e1s<\/b><\/p>\n
SELECT *\n  FROM employees\n WHERE department_id = 50 AND salary > 4000;\n<\/code><\/pre>\n
Employees t\u00e1bla. Minden alkalmazott list\u00e1j\u00e1nak lek\u00e9rdez\u00e9se a 20-as \u00e9s a 30-as oszt\u00e1lyb\u00f3l (department_id)
\nMegold\u00e1s<\/b><\/p>\n
SELECT *\n  FROM employees\n WHERE department_id = 20 OR department_id = 30;\n<\/code><\/pre>\n
Employees t\u00e1bla. K\u00e9rje le az \u00f6sszes munkav\u00e1llal\u00f3 list\u00e1j\u00e1t, akinek a nev\u00e9nek utols\u00f3 bet\u0171je ‘a’
\nMegold\u00e1s<\/b><\/p>\n
SELECT *\n  FROM employees\n WHERE first_name LIKE '%a';\n<\/code><\/pre>\n
Employees t\u00e1bla. Minden alkalmazott list\u00e1j\u00e1nak lek\u00e9rdez\u00e9se az 50-es \u00e9s 80-as oszt\u00e1lyb\u00f3l (department_id), akiknek van jutalma (az commission_pct oszlop nem \u00fcres)
\nMegold\u00e1s<\/b><\/p>\n
SELECT *\n  FROM employees\n WHERE     (department_id = 50 OR department_id = 80)\n       AND commission_pct IS NOT NULL;\n<\/code><\/pre>\n
Employees t\u00e1bla. K\u00e9rje le az \u00f6sszes munkav\u00e1llal\u00f3 list\u00e1j\u00e1t, akinek a nev\u00e9ben legal\u00e1bb 2 ‘n’ bet\u0171 tal\u00e1lhat\u00f3
\nMegold\u00e1s<\/b><\/p>\n
SELECT *\n  FROM employees\n WHERE first_name LIKE '%n%n%';\n<\/code><\/pre>\n
Employees t\u00e1bla. Minden alkalmazott list\u00e1j\u00e1nak lek\u00e9rdez\u00e9se, akinek a neve hosszabb mint 4 bet\u0171
\nMegold\u00e1s<\/b><\/p>\n
SELECT *\n  FROM employees\n WHERE first_name LIKE '%_____%';\n<\/code><\/pre>\n
Employees t\u00e1bla. K\u00e9rje le az \u00f6sszes munkav\u00e1llal\u00f3 list\u00e1j\u00e1t, akinek a fizet\u00e9se 8000 \u00e9s 9000 k\u00f6z\u00f6tt van (bele\u00e9rtve).
\nMegold\u00e1s<\/b><\/p>\n
SELECT *\n  FROM employees\n WHERE salary BETWEEN 8000 AND 9000;\n<\/code><\/pre>\n
Employees t\u00e1bla. K\u00e9rje le az \u00f6sszes munkav\u00e1llal\u00f3 list\u00e1j\u00e1t, akinek a nev\u00e9ben szerepel a ‘%’ karakter
\nMegold\u00e1s<\/b><\/p>\n
SELECT *\n  FROM employees\n WHERE first_name LIKE '%%%' ESCAPE '';\n<\/code><\/pre>\n
Employees t\u00e1bla. K\u00e9rje le az \u00f6sszes menedzser azonos\u00edt\u00f3j\u00e1t.
\nMegold\u00e1s<\/b><\/p>\n
SELECT DISTINCT manager_id\n  FROM employees\n WHERE manager_id IS NOT NULL;\n<\/code><\/pre>\n
Employees t\u00e1bla. K\u00e9rje le a munkav\u00e1llal\u00f3k list\u00e1j\u00e1t poz\u00edci\u00f3ik szerint a k\u00f6vetkez\u0151 form\u00e1tumban: Donald(sh_clerk).
\nMegold\u00e1s<\/b><\/p>\n
SELECT first_name || '(' || LOWER (job_id) || ')' employee FROM employees;\n<\/code><\/pre>\n
\nEgysoros f\u00fcggv\u00e9nyek haszn\u00e1lata az output testreszab\u00e1s\u00e1hoz.<\/b><\/p>\n
Employees t\u00e1bla. K\u00e9rje le az \u00f6sszes munkav\u00e1llal\u00f3 list\u00e1j\u00e1t, akinek a neve hosszabb, mint 10 karakter.
\nMegold\u00e1s<\/b><\/p>\n
SELECT *\n  FROM employees\n WHERE LENGTH (first_name) > 10;\n<\/code><\/pre>\n
Employees t\u00e1bla. K\u00e9rje le az \u00f6sszes munkav\u00e1llal\u00f3 list\u00e1j\u00e1t, akinek a nev\u00e9ben van ‘b’ bet\u0171 (nagybet\u0171k n\u00e9lk\u00fcl)
\nMegold\u00e1s<\/b><\/p>\n
SELECT *\n  FROM employees\n WHERE INSTR (LOWER (first_name), 'b') > 0;\n<\/code><\/pre>\n
Employees t\u00e1bla. K\u00e9rje le az \u00f6sszes munkav\u00e1llal\u00f3 list\u00e1j\u00e1t, akinek a nev\u00e9ben legal\u00e1bb 2 ‘a’ bet\u0171 tal\u00e1lhat\u00f3
\nMegold\u00e1s<\/b><\/p>\n
SELECT *\n  FROM employees\n WHERE INSTR (LOWER (first_name),'a',1,2) > 0;\n<\/code><\/pre>\n
Employees t\u00e1bla. K\u00e9rje le az \u00f6sszes munkav\u00e1llal\u00f3t, akinek a fizet\u00e9se 1000-re oszthat\u00f3.
\nMegold\u00e1s<\/b><\/p>\n
SELECT *\n  FROM employees\n WHERE MOD (salary, 1000) = 0;\n<\/code><\/pre>\n
Employees t\u00e1bla. K\u00e9rje le a munkav\u00e1llal\u00f3 telefonj\u00e1nak els\u0151 h\u00e1rom sz\u00e1mjegy\u00e9t, ha a sz\u00e1ma XXX.XXX.XXXX form\u00e1tum\u00fa.
\nMegold\u00e1s<\/b><\/p>\n
SELECT phone_number, SUBSTR (phone_number, 1, 3) new_phone_number\n  FROM employees\n WHERE phone_number LIKE '___.___.____';\n<\/code><\/pre>\n
Departments t\u00e1bla. K\u00e9rje le a r\u00e9szleg nev\u00e9n bel\u00fcl az els\u0151 sz\u00f3t, azok sz\u00e1m\u00e1ra, akiknek a nev\u00fckben t\u00f6bb mint egy sz\u00f3 szerepel.
\nMegold\u00e1s<\/b><\/p>\n
SELECT department_name,\n       SUBSTR (department_name, 1, INSTR (department_name, ' ')-1)\n           first_word\n  FROM departments\n WHERE INSTR (department_name, ' ') > 0;\n<\/code><\/pre>\n
Employees t\u00e1bla. K\u00e9rje le a munkav\u00e1llal\u00f3k neveit az els\u0151 \u00e9s az utols\u00f3 bet\u0171 n\u00e9lk\u00fcl.
\nMegold\u00e1s<\/b><\/p>\n
SELECT first_name, SUBSTR (first_name, 2, LENGTH (first_name) - 2) new_name\n  FROM employees;\n<\/code><\/pre>\n
Employees t\u00e1bla. K\u00e9rje le az \u00f6sszes munkav\u00e1llal\u00f3 list\u00e1j\u00e1t, akinek a nev\u00e9nek utols\u00f3 bet\u0171je ‘m’ \u00e9s a neve hosszabb, mint 5 karakter
\nMegold\u00e1s<\/b><\/p>\n
SELECT *\n  FROM employees\n WHERE SUBSTR (first_name, -1) = 'm' AND LENGTH(first_name) > 5;\n<\/code><\/pre>\n
Dual t\u00e1bla. K\u00e9rje le a k\u00f6vetkez\u0151 p\u00e9nteki d\u00e1tumot.
\nMegold\u00e1s<\/b><\/p>\n
SELECT NEXT_DAY (SYSDATE, 'FRIDAY') next_friday FROM DUAL;\n<\/code><\/pre>\n
Employees t\u00e1bla. K\u00e9rje le az \u00f6sszes munkav\u00e1llal\u00f3t, akik t\u00f6bb mint 17 \u00e9ve dolgoznak a c\u00e9gn\u00e9l.
\nMegold\u00e1s<\/b><\/p>\n
SELECT *\n  FROM employees\n WHERE MONTHS_BETWEEN (SYSDATE, hire_date) \/ 12 > 17;\n<\/code><\/pre>\n
Employees t\u00e1bla. K\u00e9rje le az \u00f6sszes munkav\u00e1llal\u00f3t, akinek a telefonj\u00e1nak utols\u00f3 sz\u00e1mjegye p\u00e1ratlan \u00e9s h\u00e1rom sz\u00e1mjegyb\u0151l \u00e1ll, amelyeket pont v\u00e1laszt el.
\nMegold\u00e1s<\/b><\/p>\n
SELECT *\n  FROM employees\n WHERE MOD (SUBSTR (phone_number, -1), 2) != 0\n       AND INSTR (phone_number,'.',1,3) = 0;\n<\/code><\/pre>\n
Employees t\u00e1bla. K\u00e9rje le az \u00f6sszes munkav\u00e1llal\u00f3 list\u00e1j\u00e1t, akinek a job_id \u00e9rt\u00e9k\u00e9ben a ‘_’ karakter ut\u00e1n legal\u00e1bb 3 karakter van, de ez az \u00e9rt\u00e9k nem ‘CLERK’
\nMegold\u00e1s<\/b><\/p>\n
SELECT *\n  FROM employees\n WHERE     LENGTH (SUBSTR (job_id, INSTR (job_id, '_') + 1)) > 3\n       AND SUBSTR (job_id, INSTR (job_id, '_') + 1) != 'CLERK';\n<\/code><\/pre>\n
Employees t\u00e1bla. K\u00e9rje le az \u00f6sszes munkav\u00e1llal\u00f3 list\u00e1j\u00e1t, cser\u00e9lje ki a PHONE_NUMBER \u00e9rt\u00e9k\u00e9ben a ‘.’ karaktert ‘-‘ karakterre
\nMegold\u00e1s<\/b><\/p>\n
SELECT phone_number, REPLACE (phone_number, '.', '-') new_phone_number\n  FROM employees;\n<\/code><\/pre>\n
\n\u00c1talak\u00edt\u00f3 f\u00fcggv\u00e9nyek \u00e9s felt\u00e9teles kifejez\u00e9sek haszn\u00e1lata<\/b><\/p>\n
Employees t\u00e1bl\u00e1zat. Szerezze meg az \u00f6sszes alkalmazott list\u00e1j\u00e1t, akik az h\u00f3nap els\u0151 napj\u00e1n (b\u00e1rmelyik) kezdt\u00e9k meg a munk\u00e1t.
\nMegold\u00e1s<\/b><\/p>\n
SELECT *\n  FROM employees\n WHERE TO_CHAR (hire_date, 'DD') = '01';\n<\/code><\/pre>\n
Employees t\u00e1bl\u00e1zat. Szerezze meg az \u00f6sszes alkalmazott list\u00e1j\u00e1t, akik 2008-ban kezdtek el dolgozni.
\nMegold\u00e1s<\/b><\/p>\n
SELECT *\n  FROM employees\n WHERE TO_CHAR (hire_date, 'YYYY') = '2008';\n<\/code><\/pre>\n
DUAL t\u00e1bl\u00e1zat. Mutassa a holnapi d\u00e1tumot a k\u00f6vetkez\u0151 form\u00e1tumban: Holnap van a h\u00f3nap m\u00e1sodik napja.
\nMegold\u00e1s<\/b><\/p>\n
SELECT TO_CHAR (SYSDATE, 'fm\"\"Holnap van \"\"Ddspth \"\"napja a\"\" H\u00f3nap')     info\n  FROM DUAL;\n<\/code><\/pre>\n
Employees t\u00e1bl\u00e1zat. Szerezze meg az \u00f6sszes alkalmazott list\u00e1j\u00e1t \u00e9s mindegyik bel\u00e9p\u00e9si d\u00e1tum\u00e1t a k\u00f6vetkez\u0151 form\u00e1tumban: j\u00fanius 21.
\nMegold\u00e1s<\/b><\/p>\n
SELECT first_name, TO_CHAR (hire_date, 'fmddth \"\"a\"\" H\u00f3nap, YYYY') hire_date\n  FROM employees;\n<\/code><\/pre>\n
Employees t\u00e1bl\u00e1zat. Szerezze meg az \u00f6sszes alkalmazott list\u00e1j\u00e1t, akiknek a fizet\u00e9s\u00e9t 20%-kal megemelt\u00e9k. A fizet\u00e9st doll\u00e1rjelk\u00e9nt mutassa.
\nMegold\u00e1s<\/b><\/p>\n
SELECT first_name, TO_CHAR (salary + salary * 0.20, 'fm$999,999.00') new_salary\n  FROM employees;\n<\/code><\/pre>\n
Employees t\u00e1bl\u00e1zat. Szerezze meg az \u00f6sszes alkalmazott list\u00e1j\u00e1t, akik 2007 febru\u00e1rj\u00e1ban kezdtek el dolgozni.
\nMegold\u00e1s<\/b><\/p>\n
SELECT *\n  FROM employees\n WHERE hire_date BETWEEN TO_DATE ('01.02.2007', 'DD.MM.YYYY')\n                     AND LAST_DAY (TO_DATE ('01.02.2007', 'DD.MM.YYYY'));\n\nSELECT *\n  FROM employees\n WHERE to_char(hire_date,'MM.YYYY') = '02.2007'; \n<\/code><\/pre>\n
DUAL t\u00e1bl\u00e1zat. K\u00e9rje le a jelenlegi d\u00e1tumot, + m\u00e1sodperc, + perc, + \u00f3ra, + nap, + h\u00f3nap, + \u00e9v.
\nMegold\u00e1s<\/b><\/p>\n
SELECT SYSDATE                          now,\n       SYSDATE + 1 \/ (24 * 60 * 60)     plus_second,\n       SYSDATE + 1 \/ (24 * 60)          plus_minute,\n       SYSDATE + 1 \/ 24                 plus_hour,\n       SYSDATE + 1                      plus_day,\n       ADD_MONTHS (SYSDATE, 1)          plus_month,\n       ADD_MONTHS (SYSDATE, 12)         plus_year\n  FROM DUAL;\n<\/code><\/pre>\n
Employees t\u00e1bl\u00e1zat. Szerezze meg az \u00f6sszes alkalmazott list\u00e1j\u00e1t a teljes fizet\u00e9sekkel (salary + commission_pct(%)) a k\u00f6vetkez\u0151 form\u00e1tumban: $24,000.00.
\nMegold\u00e1s<\/b><\/p>\n
SELECT first_name, salary, TO_CHAR (salary + salary * NVL (commission_pct, 0), 'fm$99,999.00') full_salary\n  FROM employees;\n<\/code><\/pre>\n
Employees t\u00e1bl\u00e1zat. Szerezze meg az \u00f6sszes alkalmazott list\u00e1j\u00e1t \u00e9s az inform\u00e1ci\u00f3kat a b\u00f3nuszfizet\u00e9sr\u0151l (Igen\/Nem).
\nMegold\u00e1s<\/b><\/p>\n
SELECT first_name, commission_pct, NVL2 (commission_pct, 'Yes', 'No') has_bonus\n  FROM employees;\n<\/code><\/pre>\n
Employees t\u00e1bl\u00e1zat. Szerezze meg minden alkalmazott b\u00e9rszintjeit: 5000 alatti = Alacsony szint, 5000 vagy ann\u00e1l nagyobb \u00e9s 10000 alatti = Norm\u00e1l szint, 10000 vagy ann\u00e1l nagyobb = Magas szint.
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASSZ first_name,\n       salary,\n       ESET\n           AMIKOR salary = 5000 \u00c9S salary < 10000 AKKOR 'Norm\u00e1l'\n           EGY\u00c9BK\u00c9NT 'Magas'\n       V\u00c9GE salary_level\n  A employees-b\u0151l;\n<\/code><\/pre>\n
Countries t\u00e1bl\u00e1zat. Minden orsz\u00e1g eset\u00e9ben mutasd meg a r\u00e9gi\u00f3t, amelyben tal\u00e1lhat\u00f3: 1-Eur\u00f3pa, 2-Amerika, 3-\u00c1zsia, 4-Afrika (Join n\u00e9lk\u00fcl)
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASSZ country_name country,\n       DECODE (region_id,\n               1, 'Eur\u00f3pa',\n               2, 'Amerika',\n               3, '\u00c1zsia',\n               4, 'Afrika',\n               'Ismeretlen')\n           region\n  A countries-b\u0151l;\n\nV\u00c1LASSZ country_name\n           country,\n       ESET region_id\n           AMIKOR 1 AKKOR 'Eur\u00f3pa'\n           AMIKOR 2 AKKOR 'Amerika'\n           AMIKOR 3 AKKOR '\u00c1zsia'\n           AMIKOR 4 AKKOR 'Afrika'\n           EGY\u00c9BK\u00c9NT 'Ismeretlen'\n       V\u00c9GE\n           region\n  A countries-b\u0151l;\n<\/code><\/pre>\n
\nAggreg\u00e1lt Adatok Jelent\u00e9se Csoport Funkci\u00f3kkal<\/b><\/p>\n
Employees t\u00e1bl\u00e1zat. K\u00e9sz\u00edts jelent\u00e9st department_id alapj\u00e1n a legkisebb \u00e9s legnagyobb fizet\u00e9ssel, a legkor\u00e1bbi \u00e9s legk\u00e9s\u0151bbi munk\u00e1ba \u00e1ll\u00e1s d\u00e1tum\u00e1val \u00e9s a dolgoz\u00f3k sz\u00e1m\u00e1val. Rendez\u00e9s a dolgoz\u00f3k sz\u00e1ma szerint (cs\u00f6kken\u0151 sorrendben)
\nMegold\u00e1s<\/b><\/p>\n
  V\u00c1LASSZ department_id,\n         MIN (salary) min_salary,\n         MAX (salary) max_salary,\n         MIN (hire_date) min_hire_date,\n         MAX (hire_date) max_hire_Date,\n         COUNT (*) count\n    A employees-b\u0151l\nGROUP BY department_id\norder by count(*) desc;\n<\/code><\/pre>\n
Employees t\u00e1bl\u00e1zat. H\u00e1ny dolgoz\u00f3 van, akinek a neve egy \u00e9s ugyanazon bet\u0171vel kezd\u0151dik? Rendez\u00e9s a sz\u00e1m szerint. Csak azok jelenjenek meg, ahol a sz\u00e1m nagyobb mint 1
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASSZ SUBSTR (first_name, 1, 1) first_char, COUNT (*)\n    A employees-b\u0151l\nGROUP BY SUBSTR (first_name, 1, 1)\n  HAVING COUNT (*) > 1\nORDER BY 2 DESC;\n<\/code><\/pre>\n
Employees t\u00e1bl\u00e1zat. H\u00e1ny dolgoz\u00f3 van, aki ugyanabban az oszt\u00e1lyban dolgozik \u00e9s azonos fizet\u00e9st kap?
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASSZ department_id, salary, COUNT (*)\n    A employees-b\u0151l\nGROUP BY department_id, salary\n  HAVING COUNT (*) > 1;\n<\/code><\/pre>\n
Employees t\u00e1bl\u00e1zat. K\u00e9sz\u00edts jelent\u00e9st arr\u00f3l, h\u00e1ny dolgoz\u00f3t vettek fel minden h\u00e9ten. Rendez\u00e9s a sz\u00e1m szerint
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASSZ TO_CHAR (hire_Date, 'Napi') nap, COUNT (*)\n    A employees-b\u0151l\nGROUP BY TO_CHAR (hire_Date, 'Napi')\nORDER BY 2 DESC;\n<\/code><\/pre>\n
Employees t\u00e1bl\u00e1zat. K\u00e9sz\u00edts jelent\u00e9st arr\u00f3l, h\u00e1ny dolgoz\u00f3t vettek fel \u00e9venk\u00e9nt. Rendez\u00e9s a sz\u00e1m szerint
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASSZ TO_CHAR (hire_date, '\u00c9v') \u00e9v, COUNT (*)\n    A employees-b\u0151l\nGROUP BY TO_CHAR (hire_date, '\u00c9v');\n<\/code><\/pre>\n
Employees t\u00e1bl\u00e1zat. H\u00e1ny oszt\u00e1ly van, ahol dolgoz\u00f3k vannak
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASSZ COUNT (COUNT (*))     department_count\n    A employees-b\u0151l\n   WHERE department_id IS NOT NULL\nGROUP BY department_id;\n<\/code><\/pre>\n
Employees t\u00e1bl\u00e1zat. K\u00e9sz\u00edts egy list\u00e1t department_id-r\u00f3l, ahol t\u00f6bb mint 30 dolgoz\u00f3 dolgozik.
\nMegold\u00e1s<\/b><\/p>\n
  V\u00c1LASSZ department_id\n    A employees-b\u0151l\nGROUP BY department_id\n  HAVING COUNT (*) > 30;\n<\/code><\/pre>\n
Employees t\u00e1bl\u00e1zat. K\u00e9sz\u00edts egy list\u00e1t department_id-r\u00f3l \u00e9s a kerek\u00edtett \u00e1tlagfizet\u00e9sr\u0151l minden oszt\u00e1lyban. 
\nMegold\u00e1s<\/b><\/p>\n
  V\u00c1LASSZ department_id, ROUND (AVG (salary)) avg_salary\n    A employees-b\u0151l\nGROUP BY department_id;\n<\/code><\/pre>\n
Countries t\u00e1bl\u00e1zat. K\u00e9sz\u00edts egy list\u00e1t region_id-r\u00f3l, ahol az orsz\u00e1gnevek \u00f6sszes bet\u0171je t\u00f6bb mint 60.
\nMegold\u00e1s<\/b><\/p>\n
  V\u00e1lassza ki a region_id-t a countries t\u00e1bl\u00e1zatb\u00f3l, csoportos\u00edtva region_id szerint, HAVING SUM (LENGTH (country_name)) > 60;\n<\/code><\/pre>\n
Employees t\u00e1bl\u00e1zat. K\u00e9rje el az \u00f6sszes department_id-t, ahol t\u00f6bb (>1) job_id-j\u00fa munkav\u00e1llal\u00f3k dolgoznak.
\nMegold\u00e1s<\/b><\/p>\n
  V\u00e1lassza ki a department_id-t az employees t\u00e1bl\u00e1zatb\u00f3l, csoportos\u00edtva department_id szerint, HAVING COUNT (DISTINCT job_id) > 1;\n<\/code><\/pre>\n
Employees t\u00e1bl\u00e1zat. K\u00e9rje el azoknak a manager_id-knek a list\u00e1j\u00e1t, akiknek a k\u00f6zvetlen beosztottjaik sz\u00e1ma t\u00f6bb mint 5, \u00e9s a beosztottjaik \u00f6sszes fizet\u00e9se meghaladja az 50000-et.
\nMegold\u00e1s<\/b><\/p>\n
  V\u00e1lassza ki a manager_id-t az employees t\u00e1bl\u00e1zatb\u00f3l, csoportos\u00edtva manager_id szerint, HAVING COUNT (*) > 5 AND SUM (salary) > 50000;\n<\/code><\/pre>\n
Employees t\u00e1bl\u00e1zat. K\u00e9rje el azoknak a manager_id-knek a list\u00e1j\u00e1t, akiknek a k\u00f6zvetlen beosztottjaik \u00e1tlagos fizet\u00e9se 6000 \u00e9s 9000 k\u00f6z\u00e9 esik, \u00e9s nem kapnak jutalmat (commission_pct \u00fcres).
\nMegold\u00e1s<\/b><\/p>\n
  V\u00e1lassza ki a manager_id-t \u00e9s az AVG (salary) avg_salary-t az employees t\u00e1bl\u00e1zatb\u00f3l, ahol commission_pct IS NULL, csoportos\u00edtva manager_id szerint, HAVING AVG (salary) BETWEEN 6000 AND 9000;\n<\/code><\/pre>\n
Employees t\u00e1bla. K\u00e9rje le a legmagasabb fizet\u00e9st az \u00f6sszes munkav\u00e1llal\u00f3 k\u00f6z\u00fcl, akinek a job_id \u00e9rt\u00e9ke ‘CLERK’ sz\u00f3ra v\u00e9gz\u0151dik
\nMegold\u00e1s<\/b><\/p>\n
V\u00e1lassza ki a MAX (salary) max_salary-t az employees t\u00e1bl\u00e1zatb\u00f3l, ahol job_id LIKE '%CLERK'; V\u00e1lassza ki a MAX (salary) max_salary-t az employees t\u00e1bl\u00e1zatb\u00f3l, ahol SUBSTR (job_id, -5) = 'CLERK';\n<\/code><\/pre>\n
Employees t\u00e1bl\u00e1zat. K\u00e9rje el a legnagyobb fizet\u00e9st az \u00f6sszes department \u00e1tlagos fizet\u00e9se k\u00f6z\u00f6tt.
\nMegold\u00e1s<\/b><\/p>\n
  V\u00e1lassza ki a MAX (AVG (salary))-t az employees t\u00e1bl\u00e1zatb\u00f3l, csoportos\u00edtva department_id szerint.\n<\/code><\/pre>\n
Employees t\u00e1bl\u00e1zat. K\u00e9rje el a munkav\u00e1llal\u00f3k sz\u00e1m\u00e1t, akiknek azonos sz\u00e1m\u00fa bet\u0171 van a nev\u00fckben. Csak azokat mutassa, akiknek a neve hosszabb, mint 5, \u00e9s a hasonl\u00f3 nev\u0171 munkav\u00e1llal\u00f3k sz\u00e1ma t\u00f6bb mint 20. Rendezze a neveket hossz\u00fas\u00e1g szerint.
\nMegold\u00e1s<\/b><\/p>\n
  SELECT LENGTH (first_name), COUNT (*) FROM employees GROUP BY LENGTH (first_name) HAVING LENGTH (first_name) > 5 AND COUNT (*) > 20 ORDER BY LENGTH (first_name); SELECT LENGTH (first_name), COUNT (*) FROM employees WHERE LENGTH (first_name) > 5 GROUP BY LENGTH (first_name) HAVING COUNT (*) > 20 ORDER BY LENGTH (first_name);\n<\/code><\/pre>\n
\nT\u00f6bb t\u00e1bl\u00e1zat adatainak megjelen\u00edt\u00e9se JOIN-ok seg\u00edts\u00e9g\u00e9vel.<\/b><\/p>\n
Employees, Departments, Locations, Countries, Regions t\u00e1bl\u00e1zat. K\u00e9rje el a r\u00e9gi\u00f3k list\u00e1j\u00e1t \u00e9s az egyes r\u00e9gi\u00f3kban dolgoz\u00f3 munkav\u00e1llal\u00f3k sz\u00e1m\u00e1t.
\nMegold\u00e1s<\/b><\/p>\n
  SELECT region_name, COUNT (*) FROM employees e JOIN departments d ON (e.department_id = d.department_id) JOIN locations l ON (d.location_id = l.location_id) JOIN countries c ON (l.country_id = c.country_id) JOIN regions r ON (c.region_id = r.region_id) GROUP BY region_name;\n<\/code><\/pre>\n
Employees, Departments, Locations, Countries, Regions t\u00e1bl\u00e1zat. K\u00e9rje el minden munkav\u00e1llal\u00f3 r\u00e9szletes inform\u00e1ci\u00f3it:
\nFirst_name, Last_name, Department, Job, Street, Country, Region.
\nMegold\u00e1s<\/b><\/p>\n
SELECT First_name, Last_name, Department_name, Job_id, street_address, Country_name, Region_name FROM employees e JOIN departments d ON (e.department_id = d.department_id) JOIN locations l ON (d.location_id = l.location_id) JOIN countries c ON (l.country_id = c.country_id) JOIN regions r ON (c.region_id = r.region_id);\n<\/code><\/pre>\n
Employees t\u00e1bl\u00e1zat. Mutassa meg azokat a menedzsereket, akiknek t\u00f6bb mint 6 beosztottjuk van.
\nMegold\u00e1s<\/b><\/p>\n
  V\u00c1LASZ m.first_name, COUNT (*)\n    A munkat\u00e1rsak emp csatlakoz\u00e1sa a munkat\u00e1rsak man-on (emp.manager_id = man.employee_id)\nGROUP BY man.first_name\n  HAVING COUNT (*) > 6;\n<\/code><\/pre>\n
Munkat\u00e1rsak t\u00e1bl\u00e1zata. Mutassa meg az \u00f6sszes munkat\u00e1rsat, akiknek nincs felettese.
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASZ emp.first_name\n  A munkat\u00e1rsak emp\n       BAL OLDALI CSATLAKOZ\u00c1S a munkat\u00e1rsak man ON (emp.manager_id = man.employee_id)\n HOL man.FIRST_NAME IS NULL;\n\nV\u00c1LASZ first_name\n  A munkat\u00e1rsak\n HOL manager_id IS NULL;\n<\/code><\/pre>\n
Munkat\u00e1rsak, Munka-t\u00f6rt\u00e9net t\u00e1bl\u00e1zata. A Munkat\u00e1rsak t\u00e1bl\u00e1zatban tal\u00e1lhat\u00f3 az \u00f6sszes munkat\u00e1rs. A Munka-t\u00f6rt\u00e9net t\u00e1bl\u00e1zatban tal\u00e1lhat\u00f3k azok a munkat\u00e1rsak, akik elhagyt\u00e1k a c\u00e9get. K\u00e9sz\u00edtsen jelent\u00e9st az \u00f6sszes munkat\u00e1rsr\u00f3l \u00e9s st\u00e1tuszukr\u00f3l a c\u00e9gben (Jelenleg dolgozik vagy t\u00e1vozott a c\u00e9gb\u0151l a t\u00e1voz\u00e1s d\u00e1tum\u00e1val).
\nP\u00e9lda:
\nfirst_name | st\u00e1tusz
\nJennifer | Kil\u00e9pett a c\u00e9gb\u0151l 2006. december 31-\u00e9n
\nClara | Jelenleg dolgozik
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASZ first_name,\n       NVL2 (\n           end_date,\n           TO_CHAR (end_date, 'fm\"\"Kil\u00e9pett a c\u00e9gb\u0151l\"\" DD \"\"-\u00e1n\"\" H\u00f3nap, YYYY'),\n           'Jelenleg dolgozik')\n           st\u00e1tusz\n  A munkat\u00e1rsak e BAL OLDALI CSATLAKOZ\u00c1S munka_t\u00f6rt\u00e9net j ON (e.employee_id = j.employee_id);\n<\/code><\/pre>\n
Munkat\u00e1rsak, Oszt\u00e1lyok, Helyek, Orsz\u00e1gok, R\u00e9gi\u00f3k t\u00e1bl\u00e1zata. K\u00e9sz\u00edtsen list\u00e1t az eur\u00f3pai (region_name) munkat\u00e1rsakr\u00f3l.
\nMegold\u00e1s<\/b><\/p>\n
 V\u00c1LASZ first_name\n  A munkat\u00e1rsak\n       CSATLAKOZ\u00c1S az oszt\u00e1lyokkal a department_id-n kereszt\u00fcl\n       CSATLAKOZ\u00c1S a helyekkel a location_id-n kereszt\u00fcl\n       CSATLAKOZ\u00c1S az orsz\u00e1gokkal a country_id-n kereszt\u00fcl\n       CSATLAKOZ\u00c1S a r\u00e9gi\u00f3kkal a region_id-n kereszt\u00fcl\n HOL region_name = 'Eur\u00f3pa';\n \n V\u00c1LASZ first_name\n  A munkat\u00e1rsak e\n       CSATLAKOZ\u00c1S az oszt\u00e1lyokkal d ON (e.department_id = d.department_id)\n       CSATLAKOZ\u00c1S a helyekkel l ON (d.location_id = l.location_id)\n       CSATLAKOZ\u00c1S az orsz\u00e1gokkal c ON (l.country_id = c.country_id)\n       CSATLAKOZ\u00c1S a r\u00e9gi\u00f3kkal r ON (c.region_id = r.region_id)\n HOL region_name = 'Eur\u00f3pa';\n<\/code><\/pre>\n
Munkat\u00e1rsak, Oszt\u00e1lyok t\u00e1bl\u00e1zata. Mutassa meg azokat az oszt\u00e1lyokat, ahol t\u00f6bb mint 30 munkat\u00e1rs dolgozik.
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASZ department_name, COUNT (*)\n    A munkat\u00e1rsak e CSATLAKOZ\u00c1S az oszt\u00e1lyokkal d ON (e.department_id = d.department_id)\nGROUP BY department_name\n  HAVING COUNT (*) > 30;\n<\/code><\/pre>\n
Munkat\u00e1rsak, Oszt\u00e1lyok t\u00e1bl\u00e1zata. Mutassa meg az \u00f6sszes munkat\u00e1rsat, akik nem tartoznak egyetlen oszt\u00e1lyhoz sem.
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASZ first_name\n  A munkat\u00e1rsak e\n       BAL OLDALI CSATLAKOZ\u00c1S az oszt\u00e1lyokkal d ON (e.department_id = d.department_id)\n HOL d.department_name IS NULL;\n\nV\u00c1LASZ first_name\n  A munkat\u00e1rsak\n HOL department_id IS NULL;\n<\/code><\/pre>\n
Munkat\u00e1rsak, Oszt\u00e1lyok t\u00e1bl\u00e1zata. Mutassa meg az \u00f6sszes oszt\u00e1lyt, ahol nincs egyetlen munkat\u00e1rsa sem.
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASZ department_name\n  A munkat\u00e1rsak e\n       JOBB OLDALI CSATLAKOZ\u00c1S az oszt\u00e1lyokkal d ON (e.department_id = d.department_id)\n HOL first_name IS NULL;\n<\/code><\/pre>\n
Munkat\u00e1rsak t\u00e1bl\u00e1zata. Mutassa meg az \u00f6sszes munkat\u00e1rsat, akiknek nincs senki, aki al\u00e1rendeltje legyen.
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASZ man.first_name\n  A munkat\u00e1rsak emp\n       JOBB OLDALI CSATLAKOZ\u00c1S a munkat\u00e1rsak man ON (emp.manager_id = man.employee_id)\n HOL emp.FIRST_NAME IS NULL;\n<\/code><\/pre>\n
Munkat\u00e1rsak, Munkak\u00f6r\u00f6k, Oszt\u00e1lyok t\u00e1bl\u00e1zata. Mutassa meg a munkat\u00e1rsakat a k\u00f6vetkez\u0151 form\u00e1tumban: First_name, Job_title, Department_name.
\nP\u00e9lda:
\nFirst_name | Munkak\u00f6r | Oszt\u00e1ly neve
\nDonald | Sz\u00e1ll\u00edt\u00e1s | Rakt\u00e1ros
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASZ first_name, job_title, department_name\n  A munkat\u00e1rsak e\n       CSATLAKOZ\u00c1S a munkak\u00f6r\u00f6kkel j ON (e.job_id = j.job_id)\n       CSATLAKOZ\u00c1S az oszt\u00e1lyokkal d ON (d.department_id = e.department_id);\n<\/code><\/pre>\n
Munkat\u00e1rsak t\u00e1bl\u00e1zata. K\u00e9sz\u00edtsen list\u00e1t azokr\u00f3l a munkat\u00e1rsakr\u00f3l, akiknek a menedzserei 2005-ben kezdtek dolgozni, de \u0151k maguk 2005 el\u0151tt vettek fel \u00e1ll\u00e1st.
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASZ emp.*\n  A munkav\u00e1llal\u00f3k emp JOIN munkav\u00e1llal\u00f3k man ON (emp.manager_id = man.employee_id)\n HOL A TO_CHAR (man.hire_date, 'YYYY') = '2005'\n       \u00c9S emp.hire_date < TO_DATE ('01012005', 'DDMMYYYY');\n<\/code><\/pre>\n
Munkav\u00e1llal\u00f3i t\u00e1bl\u00e1zat. K\u00e9sz\u00edtsen list\u00e1t azokr\u00f3l a munkav\u00e1llal\u00f3kr\u00f3l, akiknek a menedzsere janu\u00e1r h\u00f3napban \u00e1llt munk\u00e1ba, \u00e9s a munkak\u00f6r megnevez\u00e9se (job_title) hosszabb mint 15 karakter.
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASZ emp.*\n  A munkav\u00e1llal\u00f3k emp\n       JOIN munkav\u00e1llal\u00f3k man ON (emp.manager_id = man.employee_id)\n       JOIN munkak\u00f6r\u00f6k j ON (emp.job_id = j.job_id)\n HOL A TO_CHAR (man.hire_date, 'MM') = '01' \u00c9S A HOSSZ (j.job_title) > 15;\n<\/code><\/pre>\n
\nAlk\u00e9rd\u00e9sek haszn\u00e1lata a lek\u00e9rdez\u00e9sek megold\u00e1s\u00e1ra<\/b><\/p>\n
Munkav\u00e1llal\u00f3i t\u00e1bl\u00e1zat. K\u00e9sz\u00edtsen list\u00e1t azokr\u00f3l a munkav\u00e1llal\u00f3kr\u00f3l, akiknek a neve a leghosszabb.
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASZ *\n  A munkav\u00e1llal\u00f3kb\u00f3l\n HOL A HOSSZ (first_name) =\n       (V\u00c1LASZ MAX (HOSSZ (first_name)) A munkav\u00e1llal\u00f3kb\u00f3l);\n<\/code><\/pre>\n
Munkav\u00e1llal\u00f3i t\u00e1bl\u00e1zat. K\u00e9sz\u00edtsen list\u00e1t azokr\u00f3l a munkav\u00e1llal\u00f3kr\u00f3l, akiknek a fizet\u00e9se meghaladja az \u00f6sszes munkav\u00e1llal\u00f3 \u00e1tlagfizet\u00e9s\u00e9t.
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASZ *\n  A munkav\u00e1llal\u00f3kb\u00f3l\n HOL a fizet\u00e9s > (V\u00c1LASZ AVG (salary) A munkav\u00e1llal\u00f3kb\u00f3l);\n<\/code><\/pre>\n
Munkav\u00e1llal\u00f3i, Oszt\u00e1lyok, Helysz\u00ednek t\u00e1bl\u00e1zata. K\u00e9sz\u00edtsen list\u00e1t azokr\u00f3l a v\u00e1rosokr\u00f3l, ahol a munkav\u00e1llal\u00f3k \u00f6sszes\u00edtett j\u00f6vedelme a legalacsonyabb.
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASZ city\n    A munkav\u00e1llal\u00f3k e\n         JOIN oszt\u00e1lyok d ON (e.department_id = d.department_id)\n         JOIN helysz\u00ednek l ON (d.location_id = l.location_id)\nCsoportos\u00edt\u00e1s v\u00e1ros szerint\n  HAVING \u00d6SSZES\u00cdT\u00c9S (salary) =\n         (  V\u00c1LASZ MIN (\u00d6SSZES\u00cdT\u00c9S (salary))\n              A munkav\u00e1llal\u00f3k e\n                   JOIN oszt\u00e1lyok d ON (e.department_id = d.department_id)\n                   JOIN helysz\u00ednek l ON (d.location_id = l.location_id)\n          Csoportos\u00edt\u00e1s v\u00e1ros szerint);\n<\/code><\/pre>\n
Munkav\u00e1llal\u00f3i t\u00e1bl\u00e1zat. K\u00e9sz\u00edtsen list\u00e1t azokr\u00f3l a munkav\u00e1llal\u00f3kr\u00f3l, akiknek a menedzsere 15000-n\u00e9l magasabb fizet\u00e9st kap.
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASZ *\n  A munkav\u00e1llal\u00f3kb\u00f3l\n HOL a manager_id A (V\u00c1LASZ employee_id\n                        A munkav\u00e1llal\u00f3kb\u00f3l\n                       HOL a fizet\u00e9s > 15000)\n<\/code><\/pre>\n
Munkat\u00e1rsak, Oszt\u00e1lyok t\u00e1bl\u00e1zata. Mutassa meg az \u00f6sszes oszt\u00e1lyt, ahol nincs egyetlen munkat\u00e1rsa sem.
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASZ *\n  A oszt\u00e1lyokb\u00f3l\n HOL a department_id NEM A (V\u00c1LASZ department_id\n                               A munkav\u00e1llal\u00f3kb\u00f3l\n                              HOL a department_id NEM NULL);\n<\/code><\/pre>\n
Munkav\u00e1llal\u00f3i t\u00e1bl\u00e1zat. Mutassa be az \u00f6sszes munkav\u00e1llal\u00f3t, akik nem menedzserek.
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASZ *\n  A munkav\u00e1llal\u00f3kb\u00f3l\n HOL a employee_id NEM A (V\u00c1LASZ manager_id\n                             A munkav\u00e1llal\u00f3kb\u00f3l\n                            HOL a manager_id NEM NULL)\n<\/code><\/pre>\n
Employees t\u00e1bl\u00e1zat. Mutassa meg azokat a menedzsereket, akiknek t\u00f6bb mint 6 beosztottjuk van.
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASZ *\n  A munkav\u00e1llal\u00f3kb\u00f3l e\n HOL (V\u00c1LASZ COUNT (*)\n          A munkav\u00e1llal\u00f3kb\u00f3l\n         HOL a manager_id = e.employee_id) > 6;\n<\/code><\/pre>\n
Munkav\u00e1llal\u00f3i, Oszt\u00e1lyok t\u00e1bl\u00e1zata. Mutassa meg azokat a munkav\u00e1llal\u00f3kat, akik az IT oszt\u00e1lyban dolgoznak.
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASZ *\n  A munkav\u00e1llal\u00f3kb\u00f3l\n HOL a department_id = (V\u00c1LASZ department_id\n                          A oszt\u00e1lyokb\u00f3l\n                         HOL a department_name = 'IT');\n<\/code><\/pre>\n
Munkat\u00e1rsak, Munkak\u00f6r\u00f6k, Oszt\u00e1lyok t\u00e1bl\u00e1zata. Mutassa meg a munkat\u00e1rsakat a k\u00f6vetkez\u0151 form\u00e1tumban: First_name, Job_title, Department_name.
\nP\u00e9lda:
\nFirst_name | Munkak\u00f6r | Oszt\u00e1ly neve
\nDonald | Sz\u00e1ll\u00edt\u00e1s | Rakt\u00e1ros
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASZ first_name,\n       (V\u00c1LASZ job_title\n          A munkak\u00f6r\u00f6kb\u0151l\n         HOL a job_id = e.job_id)\n           job_title,\n       (V\u00c1LASZ department_name\n          A oszt\u00e1lyokb\u00f3l\n         HOL a department_id = e.department_id)\n           department_name\n  A munkav\u00e1llal\u00f3kb\u00f3l e;\n<\/code><\/pre>\n
Munkat\u00e1rsak t\u00e1bl\u00e1zata. K\u00e9sz\u00edtsen list\u00e1t azokr\u00f3l a munkat\u00e1rsakr\u00f3l, akiknek a menedzserei 2005-ben kezdtek dolgozni, de \u0151k maguk 2005 el\u0151tt vettek fel \u00e1ll\u00e1st.
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASZ *\n  A munkav\u00e1llal\u00f3kb\u00f3l\n HOL     manager_id A (V\u00c1LASZ employee_id\n                            A munkav\u00e1llal\u00f3kb\u00f3l\n                           HOL A TO_CHAR (hire_date, 'YYYY') = '2005')\n       \u00c9S hire_date < TO_DATE ('01012005', 'DDMMYYYY');\n<\/code><\/pre>\n
Munkav\u00e1llal\u00f3i t\u00e1bl\u00e1zat. K\u00e9sz\u00edtsen list\u00e1t azokr\u00f3l a munkav\u00e1llal\u00f3kr\u00f3l, akiknek a menedzsere janu\u00e1r h\u00f3napban \u00e1llt munk\u00e1ba, \u00e9s a munkak\u00f6r megnevez\u00e9se (job_title) hosszabb mint 15 karakter.
\nMegold\u00e1s<\/b><\/p>\n
V\u00c1LASZ *\n  A munkav\u00e1llal\u00f3kb\u00f3l e\n HOL     manager_id A (V\u00c1LASZ employee_id\n                            A munkav\u00e1llal\u00f3kb\u00f3l\n                           HOL A TO_CHAR (hire_date, 'MM') = '01')\n       \u00c9S (V\u00c1LASZ HOSSZ (job_title)\n              A munkak\u00f6r\u00f6kb\u0151l\n             HOL a job_id = e.job_id) > 15;\n<\/code><\/pre>\n
\nEddig tart.<\/b><\/p>\n
Rem\u00e9lem, a feladatok \u00e9rdekesek \u00e9s sz\u00f3rakoztat\u00f3ak voltak. 
\nAhogy lehet, kieg\u00e9sz\u00edtem ezt a feladatlokat.
\nSz\u00edvesen fogadom a megjegyz\u00e9seket \u00e9s javaslatokat is.<\/p>\n
P.S.: Ha valakinek esz\u00e9be jut egy \u00e9rdekes SELECT feladat, \u00edrjon a megjegyz\u00e9sekbe, hozz\u00e1teszem a list\u00e1hoz.<\/p>\n
K\u00f6sz\u00f6n\u00f6m.
\n
Forr\u00e1s: habr.com<\/a><\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"
\u0417\u0434\u0440\u0430\u0432\u0441\u0442\u0432\u0443\u0439, \u0425\u0430\u0431\u0440! \u0412\u043e\u0442 \u0443\u0436\u0435 \u0431\u043e\u043b\u0435\u0435 3-\u0445 \u043b\u0435\u0442 \u044f \u043f\u0440\u0435\u043f\u043e\u0434\u0430\u044e SQL \u0432 \u0440\u0430\u0437\u043d\u044b\u0445 \u0442\u0440\u0435\u043d\u0438\u043d\u0433 \u0446\u0435\u043d\u0442\u0440\u0430\u0445, \u0438 \u043e\u0434\u043d\u0438\u043c \u0438\u0437 \u043c\u043e\u0438\u0445 \u043d\u0430\u0431\u043b\u044e\u0434\u0435\u043d\u0438\u0439 \u044f\u0432\u043b\u044f\u0435\u0442\u0441\u044f \u0442\u043e, \u0447\u0442\u043e \u0441\u0442\u0443\u0434\u0435\u043d\u0442\u044b \u043e\u0441\u0432\u0430\u0438\u0432\u0430\u044e\u0442 \u0438 \u043f\u043e\u043d\u0438\u043c\u0430\u044e\u0442 SQL \u043b\u0443\u0447\u0448\u0435, \u0435\u0441\u043b\u0438 \u0441\u0442\u0430\u0432\u0438\u0442\u044c \u043f\u0435\u0440\u0435\u0434 \u043d\u0438\u043c\u0438 \u0437\u0430\u0434\u0430\u0447\u0443, \u0430 \u043d\u0435 \u043f\u0440\u043e\u0441\u0442\u043e \u0440\u0430\u0441\u0441\u043a\u0430\u0437\u044b\u0432\u0430\u0442\u044c \u043e \u0432\u043e\u0437\u043c\u043e\u0436\u043d\u043e\u0441\u0442\u044f\u0445 \u0438 \u0442\u0435\u043e\u0440\u0435\u0442\u0438\u0447\u0435\u0441\u043a\u0438\u0445 \u043e\u0441\u043d\u043e\u0432\u0430\u0445. \u0412 \u044d\u0442\u043e\u0439 \u0441\u0442\u0430\u0442\u044c\u0435 \u044f \u043f\u043e\u0434\u0435\u043b\u044e\u0441\u044c \u0441 \u0432\u0430\u043c\u0438 \u0441\u0432\u043e\u0438\u043c \u0441\u043f\u0438\u0441\u043a\u043e\u043c \u0437\u0430\u0434\u0430\u0447, \u043a\u043e\u0442\u043e\u0440\u044b\u0435 \u044f \u0434\u0430\u044e […]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":1,"featured_media":27465,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[702],"tags":[],"class_list":["post-36671","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\n","aioseo_head_json":{"title":"\ud83e\udd47SQL. \u00c9rdekes feladatok | ProHoster","description":"\u00dcdv, Habr! 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