SQLD(SQL 개발자) 기출 · 집계 함수

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1. 1.select
   count(case when 반=1 then 1 end) as "결괏값"
   count(case when 반=2 then 1 end) as b,
   count(case when 반=3 then 1 end) as c
   from SQLD_67;
2. 2.select 반,
   count(distinct 이름) AS "결괏값"
   FROM SQLD_67
   group by 반;
3. 3.select 반,
   count(1) AS "결괏값"
   FROM SQLD_67
   group by 반;
4. 4.select 반,
   count(*) AS "결괏값"
   FROM SQLD_67
   group by 반;