'SQL' SELECT 문, WHERE 조건절 (*기초 분석)

SELECT 문 기본

SELECT *
FROM employees;

테이블 모든 열 조회

 

WHERE 조건절

SELECT employee_id, first_name, last_name  
FROM   employees;

SELECT *
FROM   employees
WHERE  email LIKE 'V'||'%';

SELECT *
FROM   employees
WHERE  salary >= 6000
ORDER BY salary;

테이블 모든 열 조회

 

연산자

연산자 분류

SELECT *
FROM   employees
WHERE  salary IN (6000, 8000)
ORDER BY salary;

IN : 해당값만 출력

WHERE  email LIKE 'B'||'%'
ORDER BY salary;

WHERE  email LIKE 'B'||'_____'
ORDER BY salary;

LIKE - ‘%’

‘%’ : 모두

‘_’ : 자릿수 만큼 모두

SELECT *
FROM   employees
WHERE  manager_id IS NULL
ORDER BY salary;

IS NULL

SELECT *
FROM   employees
WHERE  salary = 8000  
AND    job_id = 'SA_REP'
ORDER BY salary;

SELECT *
FROM   employees
WHERE  salary = 8000  
OR     salary = 6000
ORDER BY salary;

WHERE - AND -OR

SELECT order_no, item_id, quantity, 
       ROUND(sales/1000,0) AS SALES_, 
       'overall_sales' AS TYPE 
FROM order_info
UNION ALL
SELECT order_no, item_id, quantity, 
       ROUND(sales/1000,0) AS SALES_, 
       'Steak' AS TYPE 
FROM order_info
WHERE item_id = 'M0005'

WHERE 조건문으로 BOXPLOT

 

 

(출처: 핵심만 쉽게, 모두의 SQL 데이터 분석)