ืืขืื, ืืืืจ!
ืคึฟืึทืจ ืืขืจ ืืื 3 ืืึธืจ ืืื ืืึธืื ืืขืืขืจื ื SQL ืืื ืคืึทืจืฉืืื ืืจืืื ืื ื ืกืขื ืืขืจืก, ืืื ืืืื ืขืจ ืคืื ืืืื ืึทืืืขืจืืืืืฉืึทื ื ืืื ืึทื ืกืืืืขื ืื ืืขื ืืื ืคึฟืึทืจืฉืืืื SQL ืืขืกืขืจ ืืืื ืืื ืืขื ืขื ืืขืืขืื ืึท ืึทืจืืขื, ืืื ื ืื ื ืึธืจ ืืขืจืฆืืืื ืืืขืื ืื ืคึผืึทืกืึทืืืืึทืืื ืืื ืืขืึธืจืขืืืฉ ืืกืืืืช.
ืืื ืืขื ืึทืจืืืงื, ืืื ืืืขื ืืืืื ืืื ืืืจ ืืืื ืจืฉืืื ืคืื ืคืจืืืืขืืขื ืืืึธืก ืืื ืืขืื ืฆื ืกืืืืขื ืื ืืื ืืขืงืฆืืขืก ืืื ืืืืฃ ืืืึธืก ืืืจ ืคืืจื ืคืึทืจืฉืืื ืืืืคึผืก ืคืื ืืจืืื ืกืืึธืจืื, ืืืึธืก ืคืืจื ืฆื ืึท ืืืฃ ืืื ืงืืึธืจ ืคืืจืฉืืื ื ืคืื SQL.
SQL (หษsหkjuหษl; ืขื ืืืืฉ ืกืืจืึทืงืืฉืขืจื ืึธื ืคึฟืจืขื ืฉืคึผืจืึทื) ืืื ืึท ืืขืงืืึทืจืึทืืืืืข ืคึผืจืึธืืจืึทืืืื ื ืฉืคึผืจืึทื ืืขื ืืฆื ืฆื ืฉืึทืคึฟื, ืืึธืืืคืืฆืืจื ืืื ืคืืจื ืืึทืื ืืื ืึท ืจืืืืืฉืึทื ืึทื ืืึทืืึทืืืืก ืืขืจืืื ืืืจื ืึท ืฆืื ืขืืขื ืืึทืืึทืืืืก ืคืึทืจืืืึทืืืื ื ืกืืกืืขื.
ืืืจ ืงืขื ืขื ืืืืขื ืขื ืืืขืื SQL ืคึฟืื ืคืึทืจืฉืืื .
ืืขืจ ืึทืจืืืงื ืืื ื ืืฉื ืืืขื ืฆื ืืขืจื ืขื ืืืจ SQL ืคึฟืื ืงืจืึทืฆื.
ืึทืืื ืืึธืื ืก ืืืื.
ืืืจ ืืืขืื ื ืืฆื ืื ืืืงืื ื ืืื ืึธืจืึทืงืืข ืืื ืืืจืข ืืืฉื ():
ืืื ืืึธื ืึทื ืืืจ ืืืขืื ืืืืื ืืึทืืจืึทืืื ืกืขืืขืงื ืืึทืกืงืก. ืขืก ืืขื ืขื ืงืืื DML ืึธืืขืจ DDL ืืึทืกืงืก ืืึธ.
ืืึทืกืงืก
ืจืืกืืจืืงืืื ื ืืื ืกืึธืจืืื ื ืืึทืื
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืืื ืืื ืคึฟืึธืจืืึทืฆืืข ืืืขืื ืึทืืข ืขืืคึผืืืืื
ืืึทืฉืืื
SELECT * FROM employees
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืึทืืข ืขืืคึผืืืืื ืืขืืืืกื 'ืืื'
ืืึทืฉืืื
SELECT *
FROM employees
WHERE first_name = 'David';
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืึทืืข ืขืืคึผืืืืื ืืื ืืืฉืึธื_ืื ืืืืึทื ืฆื 'IT_PROG'
ืืึทืฉืืื
SELECT *
FROM employees
WHERE job_id = 'IT_PROG'
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืึทืืข ืขืืคึผืืืืื ืคืื ืื 50 ืึธืคึผืืืืืื ื (ืืขืคึผืึทืจืืืขื ื_ืื) ืืื ืึท ืืขืฆืึธืื (ืืขืฆืึธืื) ืืจืขืกืขืจ ืืื 4000
ืืึทืฉืืื
SELECT *
FROM employees
WHERE department_id = 50 AND salary > 4000;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืึทืืข ืขืืคึผืืืืื ืคืื ืื 20 ืืื 30 ืึธืคึผืืืืืื ื (department_id)
ืืึทืฉืืื
SELECT *
FROM employees
WHERE department_id = 20 OR department_id = 30;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืึทืืข ืขืืคึผืืืืื ืืืขืืขื ืก ืืขืฆืืข ืืจืืื ืืื ืืืืขืจ ื ืึธืืขื ืืื 'ืึท'
ืืึทืฉืืื
SELECT *
FROM employees
WHERE first_name LIKE '%a';
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืึทืืข ืขืืคึผืืืืื ืคืื ืื 50 ืืื 80 ืึธืคึผืืืืืื ื (ืืขืคึผืึทืจืืืขื ื_ืื) ืืืึธืก ืืึธืื ืึท ืืึธื ืืก (ืื ืืืขืจื ืืื ืื ืงืึธืืืกืืข_ืคึผืงื ืืืึทื ืืื ื ืืฉื ืืืืืืง)
ืืึทืฉืืื
SELECT *
FROM employees
WHERE (department_id = 50 OR department_id = 80)
AND commission_pct IS NOT NULL;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืึทืืข ืขืืคึผืืืืื ืืืขืืขื ืก ื ืขืืขื ืึทื ืืืึทืืื ืืคึผืืืช 2 ืืืชืืืช 'n'
ืืึทืฉืืื
SELECT *
FROM employees
WHERE first_name LIKE '%n%n%';
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืึทืืข ืขืืคึผืืืืื ืืืขืืขื ืก ื ืขืืขื ืืขื ืขื ืืขืจ ืืื 4 ืืืชืืืช
ืืึทืฉืืื
SELECT *
FROM employees
WHERE first_name LIKE '%_____%';
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืึทืืข ืขืืคึผืืืืื ืืืขืืขื ืก ืืขืฆืึธืื ืืื ืืื ืื ืงืืื ืคืื 8000 ืฆื 9000 (ืื ืงืืืกืืื)
ืืึทืฉืืื
SELECT *
FROM employees
WHERE salary BETWEEN 8000 AND 9000;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืึทืืข ืขืืคึผืืืืื ืืืขืืขื ืก ื ืึธืืขื ืึผืืื ืื ืกืืืืึธื '%'
ืืึทืฉืืื
SELECT *
FROM employees
WHERE first_name LIKE '%%%' ESCAPE '';
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืึทืืข ืคืึทืจืืืึทืืืขืจ ืืืก
ืืึทืฉืืื
SELECT DISTINCT manager_id
FROM employees
WHERE manager_id IS NOT NULL;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืขืืคึผืืืืื ืืื ืืืืขืจ ืฉืืขืืขืก ืืื ืืขื ืคึฟืึธืจืืึทื: ืืึธื ืึทืื (ืฉ_ืงืืขืจืง)
ืืึทืฉืืื
SELECT first_name || '(' || LOWER (job_id) || ')' employee FROM employees;
ื ืืฆื ืืืื-ืจืืืขืจื ืคืึทื ืืงืฉืึทื ื ืฆื ืงืึทืกืืึทืืืื ืจืขืืืืืึทื
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืึทืืข ืขืืคึผืืืืื ืืืขืืขื ืก ื ืขืืขื ืืขื ืขื ืืขืจ ืืื 10 ืืืชืืืช
ืืึทืฉืืื
SELECT *
FROM employees
WHERE LENGTH (first_name) > 10;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืึทืืข ืขืืคึผืืืืื ืืืึธืก ืืึธืื ืื ืืจืืื 'ื' ืืื ืืืืขืจ ื ืึธืืขื (ืคืึทื ืื ืกืขื ืกืืืืื)
ืืึทืฉืืื
SELECT *
FROM employees
WHERE INSTR (LOWER (first_name), 'b') > 0;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืึทืืข ืขืืคึผืืืืื ืืืขืืขื ืก ื ืขืืขื ืึทื ืืืึทืืื ืืคึผืืืช 2 ืืืชืืืช 'ืึท'
ืืึทืฉืืื
SELECT *
FROM employees
WHERE INSTR (LOWER (first_name),'a',1,2) > 0;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืึทืืข ืขืืคึผืืืืื ืืืขืืขื ืก ืืขืฆืึธืื ืืื ืึท ืงืืืคื ืคืื 1000
ืืึทืฉืืื
SELECT *
FROM employees
WHERE MOD (salary, 1000) = 0;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืืขืจ ืขืจืฉืืขืจ 3-ืฆืืคึฟืขืจ ื ืืืขืจ ืคืื ืึทื ืึธื ืืขืฉืืขืืืขืจ ืก ืืขืืขืคืึธื ื ืืืขืจ ืืืื ืืืื ื ืืืขืจ ืืื ืืื ืื ืคึฟืึธืจืืึทื XXX.XXX.XXXX
ืืึทืฉืืื
SELECT phone_number, SUBSTR (phone_number, 1, 3) new_phone_number
FROM employees
WHERE phone_number LIKE '___.___.____';
ืืืคึผืึทืจืืืึทื ืฅ ืืืฉ. ืืึทืงืืืขื ืื ืขืจืฉืืขืจ ืืืึธืจื ืคืื ืื ืึธืคึผืืืืืื ื ื ืึธืืขื ืคึฟืึทืจ ืื ืืืืก ืืึธืื ืืขืจ ืืื ืืืื ืืืึธืจื ืืื ืืขื ื ืึธืืขื
ืืึทืฉืืื
SELECT department_name,
SUBSTR (department_name, 1, INSTR (department_name, ' ')-1)
first_word
FROM departments
WHERE INSTR (department_name, ' ') > 0;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึธื ืืขืฉืืขืืืขืจ ื ืขืืขื ืึธื ืขืจืฉืืขืจ ืืื ืืขืฆืืข ืืจืืื ืืื ื ืึธืืขื
ืืึทืฉืืื
SELECT first_name, SUBSTR (first_name, 2, LENGTH (first_name) - 2) new_name
FROM employees;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืึทืืข ืขืืคึผืืืืื ืืืขืืขื ืก ืืขืฆืืข ืืจืืื ืืื ืืืืขืจ ื ืึธืืขื ืืื 'm' ืืื ืืืขืืขื ืก ื ืึธืืขื ืืื ืืขืจ ืืื 5
ืืึทืฉืืื
SELECT *
FROM employees
WHERE SUBSTR (first_name, -1) = 'm' AND LENGTH(first_name)>5;
ืืืฉ ืฆืืืืืขื ืืืง. ืืึทืงืืืขื ืืืืึทืืขืจ ืคืจืืืืื ืืึทืืข
ืืึทืฉืืื
SELECT NEXT_DAY (SYSDATE, 'FRIDAY') next_friday FROM DUAL;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืึทืืข ืขืืคึผืืืืื ืืืึธืก ืืึธืื ืืขืืจืืขื ืคึฟืึทืจ ืื ืคืืจืืข ืคึฟืึทืจ ืืขืจ ืืื 17 ืืึธืจ
ืืึทืฉืืื
SELECT *
FROM employees
WHERE MONTHS_BETWEEN (SYSDATE, hire_date) / 12 > 17;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืึทืืข ืขืืคึผืืืืื ืืืขืืขื ืก ืืขืฆืืข ืฆืืคึฟืขืจ ืคืื ืืืืขืจ ืืขืืขืคืึธื ื ืืืขืจ ืืื ืืึธืื ืข ืืื ืืืฉืืืื ืคืื 3 ื ืืืขืจื ืืคืืขืฉืืืื ืืืจื ืึท ืคึผืื ืงื
ืืึทืฉืืื
SELECT *
FROM employees
WHERE MOD (SUBSTR (phone_number, -1), 2) != 0
AND INSTR (phone_number,'.',1,3) = 0;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืึทืืข ืขืืคึผืืืืื ืืืขืืขื ืก ืึทืจืืขื_ืื ืืืขืจื ื ืึธื ืื '_' ืฆืืืื ืืื ืืคึผืืืช 3 ืืืชืืืช, ืึธืืขืจ ืื ืืืขืจื ื ืึธื ืื '_' ืืื ื ืืฉื ืืืืึทื ืฆื 'CLERK'
ืืึทืฉืืื
SELECT *
FROM employees
WHERE LENGTH (SUBSTR (job_id, INSTR (job_id, '_') + 1)) > 3
AND SUBSTR (job_id, INSTR (job_id, '_') + 1) != 'CLERK';
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืึทืืข ืขืืคึผืืืืื ืืืจื ืจืืคึผืืืืกืื ื ืึทืืข '.' ืืื ืื PHONE_NUMBER ืืืขืจื ืืืืฃ '-'
ืืึทืฉืืื
SELECT phone_number, REPLACE (phone_number, '.', '-') new_phone_number
FROM employees;
ื ืืฆื ืงืึทื ืืืขืจืืฉืึทื ืคืึทื ืืงืฉืึทื ื ืืื ืงืึธื ืืืืืึธื ืึทื ืขืงืกืคึผืจืขืกืกืืึธื ืก
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืึทืืข ืขืืคึผืืืืื ืืืึธืก ืืขื ืขื ืืขืงืืืขื ืฆื ืึทืจืืขืื ืืืืฃ ืืขืจ ืขืจืฉืืขืจ ืืึธื ืคืื ืื ืืืืฉ (ืงืืื)
ืืึทืฉืืื
SELECT *
FROM employees
WHERE TO_CHAR (hire_date, 'DD') = '01';
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืึทืืข ืขืืคึผืืืืื ืืืึธืก ืืขื ืขื ืืขืงืืืขื ืฆื ืึทืจืืขืื ืืื 2008
ืืึทืฉืืื
SELECT *
FROM employees
WHERE TO_CHAR (hire_date, 'YYYY') = '2008';
ืืืฉ ืฆืืืืืขื ืืืง. ืืืืึทืื ืืึธืจืื ืก ืืึธื ืืื ืืขื ืคึฟืึธืจืืึทื: ืืึธืจืื ืืื ืืขืจ ืฆืืืืืืขืจ ืืึธื ืคืื ืืื ืืืจ
ืืึทืฉืืื
SELECT TO_CHAR (SYSDATE, 'fm""Tomorrow is ""Ddspth ""day of"" Month') info
FROM DUAL;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืึทืืข ืขืืคึผืืืืื ืืื ืื ืืึทืืข ืืืึธืก ืืขืืขืจ ืึธื ืืขืฉืืขืืืขืจ ืืื ืื ืืขืงืืืขื ืืื ืึทืจืืขื ืืื ืืขื ืคึฟืึธืจืืึทื: ืืื ื 21, 2007
ืืึทืฉืืื
SELECT first_name, TO_CHAR (hire_date, 'fmddth ""of"" Month, YYYY') hire_date
FROM employees;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืขืืคึผืืืืื ืืื ืืขืืืืงืกื ืกืึทืืขืจืื ืืืจื 20%. ืืืืึทืื ืืขืฆืึธืื ืืื ืืึธืืึทืจ ืฆืืืื
ืืึทืฉืืื
SELECT first_name, TO_CHAR (salary + salary * 0.20, 'fm$999,999.00') new_salary
FROM employees;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืึทืืข ืขืืคึผืืืืื ืืืึธืก ืื ืืขืืืืื ืืจืืขืื ืืื ืคืขืืจืืืจ 2007.
ืืึทืฉืืื
SELECT *
FROM employees
WHERE hire_date BETWEEN TO_DATE ('01.02.2007', 'DD.MM.YYYY')
AND LAST_DAY (TO_DATE ('01.02.2007', 'DD.MM.YYYY'));
SELECT *
FROM employees
WHERE to_char(hire_date,'MM.YYYY') = '02.2007';
ืืืฉ ืฆืืืืืขื ืืืง. ืืจืขื ืืขื ืื ืงืจืึทื ื ืืึทืืข, + ืจืืข, + ืืื ืื, + ืฉืขื, + ืืึธื, + ืืืืฉ, + ืืึธืจ
ืืึทืฉืืื
SELECT SYSDATE now,
SYSDATE + 1 / (24 * 60 * 60) plus_second,
SYSDATE + 1 / (24 * 60) plus_minute,
SYSDATE + 1 / 24 plus_hour,
SYSDATE + 1 plus_day,
ADD_MONTHS (SYSDATE, 1) plus_month,
ADD_MONTHS (SYSDATE, 12) plus_year
FROM DUAL;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืึทืืข ืขืืคึผืืืืื ืืื ืคืื ืกืึทืืขืจืื (ืืขืฆืึธืื + ืงืึธืืืืกืืข_ืคึผืงื (%)) ืืื ืืขื ืคึฟืึธืจืืึทื: $ 24,000.00
ืืึทืฉืืื
SELECT first_name, salary, TO_CHAR (salary + salary * NVL (commission_pct, 0), 'fm$99,999.00') full_salary
FROM employees;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืึทืืข ืขืืคึผืืืืื ืืื ืืื ืคึฟืึธืจืืึทืฆืืข ืืืขืื ืื ืึทืืืืืืึทืืืืึทืื ืคืื ืืขืฆืึธืื ืืึธื ืืกืขืก (ืืึธ / ื ืืื)
ืืึทืฉืืื
SELECT first_name, commission_pct, NVL2 (commission_pct, 'Yes', 'No') has_bonus
FROM employees;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืื ืืขืฆืึธืื ืืืจืื ืคืื ืืขืืขืจ ืึธื ืืขืฉืืขืืืขืจ: ืืืืื ืืงืขืจ ืืื 5000 ืืื ืืขืจืขืื ื ืืื ื ืืืขืจืืง ืืืจืื, ืืจืขืกืขืจ ืืื ืึธืืขืจ ืืืืึทื ืฆื 5000 ืืื ืืืืื ืืงืขืจ ืืื 10000 ืืื ืืขืืืืื ื ืึธืจืืึทื ืืืจืื, ืืขืจ ืืื ืึธืืขืจ ืืืืึทื ืฆื 10000 ืืื ืืขืจืขืื ื ืืื ืืืื ืืืจืื
ืืึทืฉืืื
SELECT first_name,
salary,
CASE
WHEN salary < 5000 THEN 'Low'
WHEN salary >= 5000 AND salary < 10000 THEN 'Normal'
ELSE 'High'
END salary_level
FROM employees;
ืืืฉ ืืขื ืืขืจ. ืคึฟืึทืจ ืืขืืขืจ ืืืื ื, ืืืืึทืื ืื ืืขืื ื ืืื ืืืึธืก ืขืก ืืื ืืืื: 1-ืืืืจืึธืคึผืข, 2-ืึทืืขืจืืงืข, 3-ืืืืข, 4-ืืคืจืืงืข (ืึธื ืคืึทืจืืื ืื)
ืืึทืฉืืื
SELECT country_name country,
DECODE (region_id,
1, 'Europe',
2, 'America',
3, 'Asia',
4, 'Africa',
'Unknown')
region
FROM countries;
SELECT country_name
country,
CASE region_id
WHEN 1 THEN 'Europe'
WHEN 2 THEN 'America'
WHEN 3 THEN 'Asia'
WHEN 4 THEN 'Africa'
ELSE 'Unknown'
END
region
FROM countries;
ืจืขืคึผืึธืจืืื ื ืึทืืืจืขืืึทืืขื ืืึทืื ื ืืฆื ืื ืืจืืคืข ืคืึทื ืืงืฉืึทื ื
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืืึทืจืืื ืืืจื department_id ืืื ืื ืืื ืืืื ืืื ืืึทืงืกืืืื ืืขืฆืึธืื, ืคืจื ืืื ืฉืคึผืขื ืืึทืืขืก ืคืื ืึธื ืงืืืขื ืืื ืึทืจืืขื ืืื ืื ื ืืืขืจ ืคืื ืขืืคึผืืืืื. ืกืึธืจืืืจื ืืืื ืื ื ืืืขืจ ืคืื ืขืืคึผืืืืื (ืึทืจืืื ืืืื)
ืืึทืฉืืื
SELECT department_id,
MIN (salary) min_salary,
MAX (salary) max_salary,
MIN (hire_date) min_hire_date,
MAX (hire_date) max_hire_Date,
COUNT (*) count
FROM employees
GROUP BY department_id
order by count(*) desc;
ืขืืคึผืืืืื ืืืฉ. ืืื ืคืืืข ืขืืคึผืืืืื ืืืขืืขื ืก ื ืขืืขื ืึธื ืืืืื ืืื ืื ืืขืืืข ืืจืืื? ืกืึธืจื ืืืจื ืงืืืึทื ืืืื. ืืืืึทืื ืืืืื ืื ืืื ืื ืงืืืึทื ืืืื ืืื ืืจืขืกืขืจ ืืื 1
ืืึทืฉืืื
SELECT SUBSTR (first_name, 1, 1) first_char, COUNT (*)
FROM employees
GROUP BY SUBSTR (first_name, 1, 1)
HAVING COUNT (*) > 1
ORDER BY 2 DESC;
ืขืืคึผืืืืื ืืืฉ. ืืื ืคืืืข ืขืืคึผืืืืื ืึทืจืืขื ืืื ืืขืจ ืืขืืืืงืขืจ ืึธืคึผืืืืืื ื ืืื ืืึทืงืืืขื ืื ืืขืืืข ืืขืฆืึธืื?
ืืึทืฉืืื
SELECT department_id, salary, COUNT (*)
FROM employees
GROUP BY department_id, salary
HAVING COUNT (*) > 1;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืืึทืจืืื ืคืื ืืื ืคืืืข ืขืืคึผืืืืื ืืขื ืขื ืืืืขืจื ืืขืืขืจ ืืึธื ืคืื ืื ืืืึธื. ืกืึธืจื ืืืจื ืงืืืึทื ืืืื
ืืึทืฉืืื
SELECT TO_CHAR (hire_Date, 'Day') day, COUNT (*)
FROM employees
GROUP BY TO_CHAR (hire_Date, 'Day')
ORDER BY 2 DESC;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืืึทืจืืื ืคืื ืืื ืคืืืข ืขืืคึผืืืืื ืืขื ืขื ืืืืขืจื ืืืจื ืืึธืจ. ืกืึธืจื ืืืจื ืงืืืึทื ืืืื
ืืึทืฉืืื
SELECT TO_CHAR (hire_date, 'YYYY') year, COUNT (*)
FROM employees
GROUP BY TO_CHAR (hire_date, 'YYYY');
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืื ื ืืืขืจ ืคืื ืืืคึผืึทืจืืืึทื ืฅ ืืืึธืก ืืึธืื ืขืืคึผืืืืื
ืืึทืฉืืื
SELECT COUNT (COUNT (*)) department_count
FROM employees
WHERE department_id IS NOT NULL
GROUP BY department_id;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืืขืคึผืึทืจืืืขื ื_ืืืก ืืืึธืก ืืึธืื ืืขืจ ืืื 30 ืขืืคึผืืืืื
ืืึทืฉืืื
SELECT department_id
FROM employees
GROUP BY department_id
HAVING COUNT (*) > 30;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืืขืคึผืึทืจืืืขื ื_ืืืก ืืื ืื ืจืึทืื ืืื ืืืจืืฉื ืืืืขื ืืขืฆืึธืื ืคืื ืขืืคึผืืืืื ืืื ืืขืืขืจ ืึธืคึผืืืืืื ื.
ืืึทืฉืืื
SELECT department_id, ROUND (AVG (salary)) avg_salary
FROM employees
GROUP BY department_id;
ืืืฉ ืืขื ืืขืจ. ืืึทืงืืืขื ืื ืจืฉืืื region_id ืื ืกืึทืืึทืงื ืคืื ืึทืืข ืืืชืืืช ืคืื ืึทืืข ืืึทื ื_ื ืึทืืขืก ืืื ืืืึธืก ืขืก ืืขื ืขื ืืขืจ ืืื 60
ืืึทืฉืืื
SELECT region_id
FROM countries
GROUP BY region_id
HAVING SUM (LENGTH (country_name)) > 60;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืืขืคึผืึทืจืืืขื ื_ืืืก ืืื ืืืึธืก ืขืืคึผืืืืื ืคืื ืขืืืขืืข (>1) ืึทืจืืขื_ืืืก ืึทืจืืขื
ืืึทืฉืืื
SELECT department_id
FROM employees
GROUP BY department_id
HAVING COUNT (DISTINCT job_id) > 1;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืืึทื ืึทืืขืจ_ืืืก ืืืขืืขื ืก ื ืืืขืจ ืคืื ืกืึทืืึธืจืืึทื ืืืฅ ืืื ืืจืขืกืขืจ ืืื 5 ืืื ืื ืกืึทืืึทืงื ืคืื ืึทืืข ืกืึทืืขืจืื ืคืื ืืืื ืกืึทืืึธืจืืึทื ืืืฅ ืืื ืืจืขืกืขืจ ืืื 50000
ืืึทืฉืืื
SELECT manager_id
FROM employees
GROUP BY manager_id
HAVING COUNT (*) > 5 AND SUM (salary) > 50000;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืืึทื ืึทืืขืจ_ืืืก ืืืขืืขื ืก ืืืจืืฉื ืืืืขื ืืขืฆืึธืื ืคืื ืึทืืข ืืืื ืกืึทืืึธืจืืึทื ืืืฅ ืืื ืืื ืื ืงืืื ืคืื 6000 ืฆื 9000 ืืื ืืืึธืก ืืึธื ื ืื ืืึทืงืืืขื ืืึธื ืืกืขืก (ืงืึธืืืกืืข_ืคึผืงื ืืื ืืืืืืง)
ืืึทืฉืืื
SELECT manager_id, AVG (salary) avg_salary
FROM employees
WHERE commission_pct IS NULL
GROUP BY manager_id
HAVING AVG (salary) BETWEEN 6000 AND 9000;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืื ืืึทืงืกืืืื ืืขืฆืึธืื ืคืื ืึทืืข ืขืืคึผืืืืื job_id ืืืึธืก ืขื ืืก ืืื ืื ืืืึธืจื 'CLERK'
ืืึทืฉืืื
SELECT MAX (salary) max_salary
FROM employees
WHERE job_id LIKE '%CLERK';
SELECT MAX (salary) max_salary
FROM employees
WHERE SUBSTR (job_id, -5) = 'CLERK';
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืื ืืึทืงืกืืืื ืืขืฆืึธืื ืฆืืืืฉื ืึทืืข ืืืจืืฉื ืืืืขื ืกืึทืืขืจืื ืคึฟืึทืจ ืื ืึธืคึผืืืืืื ื
ืืึทืฉืืื
SELECT MAX (AVG (salary))
FROM employees
GROUP BY department_id;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืื ื ืืืขืจ ืคืื ืขืืคึผืืืืื ืืื ืื ืืขืืืข ื ืืืขืจ ืคืื ืืืชืืืช ืืื ืืืืขืจ ื ืึธืืขื. ืืื ืืขืจ ืืขืืืืงืขืจ ืฆืืื, ืืืืึทืื ืืืืื ืื ืืืขืืขื ืก ื ืึธืืขื ืืขื ื ืืื ืืขืจ ืืื 5 ืืื ืื ื ืืืขืจ ืคืื ืขืืคึผืืืืื ืืื ืื ืืขืืืข ื ืึธืืขื ืืื ืืขืจ ืืื 20. ืกืึธืจื ืืืจื ื ืึธืืขื ืืขื ื
ืืึทืฉืืื
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);
ืืืืึทืื ืืืง ืืึทืื ืคึฟืื ืงืืืคื ืืืฉื ื ืืฆื ืืืฉืึธืื ืก
ืืืฉ ืขืืคึผืืืืื, ืืืคึผืึทืจืืืึทื ืฅ, ืืึธืืงืืืฉืึทื ื, ืืขื ืืขืจ, ืจืขืืืึธื ืก. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืืงืืืืช ืืื ืื ื ืืืขืจ ืคืื ืขืืคึผืืืืื ืืื ืืขืืขืจ ืืขืื ื
ืืึทืฉืืื
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;
ืืืฉ ืขืืคึผืืืืื, ืืืคึผืึทืจืืืึทื ืฅ, ืืึธืืงืืืฉืึทื ื, ืืขื ืืขืจ, ืจืขืืืึธื ืก. ืืึทืงืืืขื ืืืืืืื ืืื ืคึฟืึธืจืืึทืฆืืข ืืืขืื ืืขืืขืจ ืึธื ืืขืฉืืขืืืขืจ:
First_name, Last_name, ืืขืคึผืึทืจืืืขื ื, ืึทืจืืขื, ืกืืจืื, ืืึทื ื, ืงืื ื
ืืึทืฉืืื
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);
ืขืืคึผืืืืื ืืืฉ. ืืืืึทืื ืึทืืข ืืึทื ืึทืืืฉืขืจื ืืืึธืก ืืึธืื ืืขืจ ืืื 6 ืขืืคึผืืืืื ืกืึทืืึธืจืืึทื ืืื ืฆื ืืื
ืืึทืฉืืื
SELECT man.first_name, COUNT (*)
FROM employees emp JOIN employees man ON (emp.manager_id = man.employee_id)
GROUP BY man.first_name
HAVING COUNT (*) > 6;
ืขืืคึผืืืืื ืืืฉ. ืืืืึทืื ืึทืืข ืขืืคึผืืืืื ืืืึธืก ืืึธื ื ืื ืืึทืจืืื ืฆื ืืืขืจ ืขืก ืื
ืืึทืฉืืื
SELECT emp.first_name
FROM employees emp
LEFT JOIN employees man ON (emp.manager_id = man.employee_id)
WHERE man.FIRST_NAME IS NULL;
SELECT first_name
FROM employees
WHERE manager_id IS NULL;
ืืืฉ ืขืืคึผืืืืื, ืืืฉืึธื_ืืขืฉืืืืข. ืื ืขืืคึผืืืืขืข ืืืฉ ืกืืึธืจื ืึทืืข ืขืืคึผืืืืื. ืื ืืืฉืึธื_ืืืกืืึธืจื ืืืฉ ืกืืึธืจื ืขืืคึผืืืืื ืืืึธืก ืืึธืื ืืื ืงืก ืืขืจ ืคืืจืืข. ืืึทืงืืืขื ืึท ืืึทืจืืื ืืืขืื ืึทืืข ืขืืคึผืืืืื ืืื ืืืืขืจ ืกืืึทืืืก ืืื ืื ืคืืจืืข (ืึทืจืืขื ืึธืืขืจ ืืื ืงืก ืืขืจ ืคืืจืืข ืืื ืื ืึธืคึผืคืึธืจ ืืึธื)
ืืืึทืฉืคึผืื:
ืขืจืฉืืขืจ_ื ืึธืืขื | ืกืืึทืืืก
ืืืฉืขื ื ืืคืขืจ | ืคืืจืืืื ืื ืคืืจืืข ืืืืฃ 31 ืืขืฆืขืืืขืจ 2006
ืงืืึทืจืึท | ืืืฆื ืึทืจืืขื
ืืึทืฉืืื
SELECT first_name,
NVL2 (
end_date,
TO_CHAR (end_date, 'fm""Left the company at"" DD ""of"" Month, YYYY'),
'Currently Working')
status
FROM employees e LEFT JOIN job_history j ON (e.employee_id = j.employee_id);
ืืืฉ ืขืืคึผืืืืื, ืืืคึผืึทืจืืืึทื ืฅ, ืืึธืืงืืืฉืึทื ื, ืืขื ืืขืจ, ืจืขืืืึธื ืก. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืขืืคึผืืืืื ืืืึธืก ืืขืื ืืื ืืืืจืึธืคึผืข (ืจืขืืืึธื_ื ืึทืืข)
ืืึทืฉืืื
SELECT first_name
FROM employees
JOIN departments USING (department_id)
JOIN locations USING (location_id)
JOIN countries USING (country_id)
JOIN regions USING (region_id)
WHERE region_name = 'Europe';
SELECT first_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)
WHERE region_name = 'Europe';
ืืืฉ ืขืืคึผืืืืื, ืืืคึผืึทืจืืืึทื ืฅ. ืืืืึทืื ืึทืืข ืืืคึผืึทืจืืืึทื ืฅ ืืื ืืขืจ ืืื 30 ืขืืคึผืืืืื
ืืึทืฉืืื
SELECT department_name, COUNT (*)
FROM employees e JOIN departments d ON (e.department_id = d.department_id)
GROUP BY department_name
HAVING COUNT (*) > 30;
ืืืฉ ืขืืคึผืืืืื, ืืืคึผืึทืจืืืึทื ืฅ. ืืืืึทืื ืึทืืข ืขืืคึผืืืืื ืืืึธืก ืืขื ืขื ื ืืฉื ืืื ืงืืื ืึธืคึผืืืืืื ื
ืืึทืฉืืื
SELECT first_name
FROM employees e
LEFT JOIN departments d ON (e.department_id = d.department_id)
WHERE d.department_name IS NULL;
SELECT first_name
FROM employees
WHERE department_id IS NULL;
ืืืฉ ืขืืคึผืืืืื, ืืืคึผืึทืจืืืึทื ืฅ. ืืืืึทืื ืึทืืข ืืืคึผืึทืจืืืึทื ืฅ ืืื ืืืึธืก ืขืก ืืขื ืขื ืงืืื ืขืืคึผืืืืื
ืืึทืฉืืื
SELECT department_name
FROM employees e
RIGHT JOIN departments d ON (e.department_id = d.department_id)
WHERE first_name IS NULL;
ืขืืคึผืืืืื ืืืฉ. ืืืืึทืื ืึทืืข ืขืืคึผืืืืื ืืืึธืก ืืึธื ื ืื ืืึธืื ืืืขืจ ืขืก ืื ืกืึทืืึธืจืืึทื ืืื ืฆื ืืื
ืืึทืฉืืื
SELECT man.first_name
FROM employees emp
RIGHT JOIN employees man ON (emp.manager_id = man.employee_id)
WHERE emp.FIRST_NAME IS NULL;
ืืืฉ ืขืืคึผืืืืื, ืืืฉืึธืืก, ืืืคึผืึทืจืืืึทื ืฅ. ืืืืึทืื ืขืืคึผืืืืื ืืื ืืขื ืคึฟืึธืจืืึทื: First_name, Job_title, Department_name.
ืืืึทืฉืคึผืื:
First_name | ืืืฉืึธื_ืืืื | ืืขืคึผืึทืจืืืขื ื_ื ืึทืืข
ืืึธื ืึทืื | ืฉืืคึผืื ื | ืืึทืึทืืืขืจ ืฉืืคึผืื ื
ืืึทืฉืืื
SELECT first_name, job_title, department_name
FROM employees e
JOIN jobs j ON (e.job_id = j.job_id)
JOIN departments d ON (d.department_id = e.department_id);
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืขืืคึผืืืืื ืืืขืืขื ืก ืืึทื ืึทืืืฉืขืจื ืืึธืื ืืึทืงืืืขื ืึท ืึทืจืืขื ืืื 2005, ืึธืืขืจ ืืื ืืขืจ ืืขืืืืงืขืจ ืฆืืื, ืื ืขืืคึผืืืืื ืืื ืืึทืงืืืขื ืึท ืึทืจืืขื ืืืืืขืจ 2005
ืืึทืฉืืื
SELECT emp.*
FROM employees emp JOIN employees man ON (emp.manager_id = man.employee_id)
WHERE TO_CHAR (man.hire_date, 'YYYY') = '2005'
AND emp.hire_date < TO_DATE ('01012005', 'DDMMYYYY');
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืขืืคึผืืืืื ืืืขืืขื ืก ืืึทื ืึทืืืฉืขืจื ืืึธืื ืึท ืึทืจืืขื ืืื ืืื ืืืจ ืคืื ืงืืื ืืึธืจ ืืื ืื ืึทืจืืขื_ืืืื ืืขื ื ืคืื ืื ืขืืคึผืืืืื ืืื ืืขืจ ืืื 15 ืืืชืืืช
ืืึทืฉืืื
SELECT emp.*
FROM employees emp
JOIN employees man ON (emp.manager_id = man.employee_id)
JOIN jobs j ON (emp.job_id = j.job_id)
WHERE TO_CHAR (man.hire_date, 'MM') = '01' AND LENGTH (j.job_title) > 15;
ื ืืฆื ืกืืืงืืืขืจืื ืฆื ืกืึธืืืืข ืงืืืขืจืื
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืขืืคึผืืืืื ืืื ืื ืืึธื ืืขืกื ื ืึธืืขื.
ืืึทืฉืืื
SELECT *
FROM employees
WHERE LENGTH (first_name) =
(SELECT MAX (LENGTH (first_name)) FROM employees);
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืขืืคึผืืืืื ืืื ืึท ืืขืฆืึธืื ืืขืืขืจ ืืื ืื ืืืจืืฉื ืืืืขื ืืขืฆืึธืื ืคืื ืึทืืข ืขืืคึผืืืืื.
ืืึทืฉืืื
SELECT *
FROM employees
WHERE salary > (SELECT AVG (salary) FROM employees);
ืขืืคึผืืืืื, ืืขืคึผืึทืจืืืขื ืฅ, ืืึธืืงืืืฉืึทื ื ืืืฉ. ืืึทืงืืืขื ืื ืฉืืึธื ืืื ืืืึธืก ืขืืคึผืืืืื ืืื ืืึทื ืฅ ืคืึทืจืืื ืขื ืื ืืื ืืกืืขืจ.
ืืึทืฉืืื
SELECT city
FROM employees e
JOIN departments d ON (e.department_id = d.department_id)
JOIN locations l ON (d.location_id = l.location_id)
GROUP BY city
HAVING SUM (salary) =
( SELECT MIN (SUM (salary))
FROM employees e
JOIN departments d ON (e.department_id = d.department_id)
JOIN locations l ON (d.location_id = l.location_id)
GROUP BY city);
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืขืืคึผืืืืื ืืืขืืขื ืก ืคืึทืจืืืึทืืืขืจ ื ืขืื ืึท ืืขืฆืึธืื ืคืื ืืขืจ ืืื 15000.
ืืึทืฉืืื
SELECT *
FROM employees
WHERE manager_id IN (SELECT employee_id
FROM employees
WHERE salary > 15000)
ืืืฉ ืขืืคึผืืืืื, ืืืคึผืึทืจืืืึทื ืฅ. ืืืืึทืื ืึทืืข ืืืคึผืึทืจืืืึทื ืฅ ืืื ืืืึธืก ืขืก ืืขื ืขื ืงืืื ืขืืคึผืืืืื
ืืึทืฉืืื
SELECT *
FROM departments
WHERE department_id NOT IN (SELECT department_id
FROM employees
WHERE department_id IS NOT NULL);
ืขืืคึผืืืืื ืืืฉ. ืืืืึทืื ืึทืืข ืขืืคึผืืืืื ืืืึธืก ืืขื ืขื ื ืืฉื ืืึทื ืึทืืืฉืขืจื
ืืึทืฉืืื
SELECT *
FROM employees
WHERE employee_id NOT IN (SELECT manager_id
FROM employees
WHERE manager_id IS NOT NULL)
ืขืืคึผืืืืื ืืืฉ. ืืืืึทืื ืึทืืข ืืึทื ืึทืืืฉืขืจื ืืืึธืก ืืึธืื ืืขืจ ืืื 6 ืขืืคึผืืืืื ืกืึทืืึธืจืืึทื ืืื ืฆื ืืื
ืืึทืฉืืื
SELECT *
FROM employees e
WHERE (SELECT COUNT (*)
FROM employees
WHERE manager_id = e.employee_id) > 6;
ืืืฉ ืขืืคึผืืืืื, ืืืคึผืึทืจืืืึทื ืฅ. ืืืืึทืื ืขืืคึผืืืืื ืืืึธืก ืึทืจืืขื ืืื ืื IT ืึธืคึผืืืืืื ื
ืืึทืฉืืื
SELECT *
FROM employees
WHERE department_id = (SELECT department_id
FROM departments
WHERE department_name = 'IT');
ืืืฉ ืขืืคึผืืืืื, ืืืฉืึธืืก, ืืืคึผืึทืจืืืึทื ืฅ. ืืืืึทืื ืขืืคึผืืืืื ืืื ืืขื ืคึฟืึธืจืืึทื: First_name, Job_title, Department_name.
ืืืึทืฉืคึผืื:
First_name | ืืืฉืึธื_ืืืื | ืืขืคึผืึทืจืืืขื ื_ื ืึทืืข
ืืึธื ืึทืื | ืฉืืคึผืื ื | ืืึทืึทืืืขืจ ืฉืืคึผืื ื
ืืึทืฉืืื
SELECT first_name,
(SELECT job_title
FROM jobs
WHERE job_id = e.job_id)
job_title,
(SELECT department_name
FROM departments
WHERE department_id = e.department_id)
department_name
FROM employees e;
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืขืืคึผืืืืื ืืืขืืขื ืก ืืึทื ืึทืืืฉืขืจื ืืึธืื ืืึทืงืืืขื ืึท ืึทืจืืขื ืืื 2005, ืึธืืขืจ ืืื ืืขืจ ืืขืืืืงืขืจ ืฆืืื, ืื ืขืืคึผืืืืื ืืื ืืึทืงืืืขื ืึท ืึทืจืืขื ืืืืืขืจ 2005
ืืึทืฉืืื
SELECT *
FROM employees
WHERE manager_id IN (SELECT employee_id
FROM employees
WHERE TO_CHAR (hire_date, 'YYYY') = '2005')
AND hire_date < TO_DATE ('01012005', 'DDMMYYYY');
ืขืืคึผืืืืื ืืืฉ. ืืึทืงืืืขื ืึท ืจืฉืืื ืคืื ืขืืคึผืืืืื ืืืขืืขื ืก ืืึทื ืึทืืืฉืขืจื ืืึธืื ืึท ืึทืจืืขื ืืื ืืื ืืืจ ืคืื ืงืืื ืืึธืจ ืืื ืื ืึทืจืืขื_ืืืื ืืขื ื ืคืื ืื ืขืืคึผืืืืื ืืื ืืขืจ ืืื 15 ืืืชืืืช
ืืึทืฉืืื
SELECT *
FROM employees e
WHERE manager_id IN (SELECT employee_id
FROM employees
WHERE TO_CHAR (hire_date, 'MM') = '01')
AND (SELECT LENGTH (job_title)
FROM jobs
WHERE job_id = e.job_id) > 15;
ืึทื ืก ืึทืืข ืคึฟืึทืจ ืืืฆื.
ืืื ืืึธืคึฟื ืื ืืึทืกืงืก ืืขื ืขื ืืฉืืงืึทืืืข ืืื ืืงืกืืืืื ื.
ืืื ืืืขื ืืืืื ืฆื ืืขื ืจืฉืืื ืคืื ืืึทืกืงืก ืืื ืคืื ืืื ืืขืืืขื.
ืืื ืืืขื ืืืื ืืืื ืฆืืคืจืืื ืฆื ืืึทืงืืืขื ืงืืื ืืึทืืขืจืงืื ืืขื ืืื ืคึฟืืจืืืืื.
ืคึผืก: ืืืื ืขืืขืฆืขืจ ืงืืื ืืื ืึท ืืฉืืงืึทืืืข ืืืืกืงืืืึทืื ืึทืจืืขื, ืฉืจืืึทืื ืืื ืื ืืึทืืขืจืงืื ืืขื ืืื ืืื ืืืขื ืืืืื ืขืก ืฆื ืืขืจ ืจืฉืืื.
ืืื ืง ืืืจ.
ืืงืืจ: www.habr.com