SQLD(SQL 개발자) 기출 · NULL

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1. 1.Select Case When Name IS NULL THEN '없음' ELSE '0' END AS USER_NAME
   FROM Emp;
2. 2.Select Case When Name IS NULL THEN '없음' ELSE NAME END AS USER_NAME
   FROM Emp;
3. 3.Select Case When Name IS NOT NULL THEN '0' ELSE NAME END AS USER_NAME
   FROM Emp;
4. 4.Select Case When Name IS NOT NULL THEN NAME ELSE '0' END AS USER_NAME
   FROM Emp;