MySQL IFNULL COALESCE (NVL)

comm 값을 출력할 때 NULL이면 0을 출력하는 함수

IFNULL

SELECT SAL + IFNULL(COMM, 0)
FROM EMP
WHERE ENAME = 'KING';

COALESCE

SELECT SAL + COALESCE(COMM, 0)
FROM EMP
WHERE ENAME = 'KING';

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# oracle
SELECT SAL + NVL(COMM, 0)
FROM EMP
WHERE ENAME = 'KING';