SQLD(SQL 개발자) 기출 · DML

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1. 1.SELECT CASE DEPTNO WHEN 10 THEN CASE WHEN JOB = 'CLERK' THEN 'A' ELSE 'B' END
   WHEN 20 THEN 'C' ELSE 'D'
   END FROM EMP;
2. 2.SELECT CASE WHEN DEPTNO = 10 THEN CASE WHEN JOB = 'CLERK' THEN 'A' ELSE 'B' END
   WHEN DEPTNO = 20 THEN 'C' ELSE 'D'
   END FROM EMP;
3. 3.SELECT CASE WHEN (DEPTNO = 10 AND JOB = 'CLERK') THEN 'A' ELSE 'B'
   WHEN DEPTNO = 20 THEN 'C' ELSE 'D'
   END FROM EMP;
4. 4.SELECT DECODE(DEPTNO, 10, DECODE(JOB, 'CLERK', 'A', 'B'), 20, 'C', 'D')
   FROM EMP;