Outer Join
TABLE testF
acol bcol
1 2
1 3
3 2
1 3001
TABLE testZ
bcol ccol
2 2
3 2
Inner join : testF-testZ on bcol column
select a.*,b.bcol as result from testF a
inner join testZ b
on a.bcol = b.bcol
acol bcol result
1 2 2
1 3 3
3 2 2
Will be result ,
Outer join : testF-testZ on bcol column – check isnull
MySQL/MSSQL 공통 방식
select a.*,
CASE
WHEN b.bcol IS NULL THEN 0
ELSE 1
END
from testF a
left outer join testZ b
on a.bcol = b.bcol
acol bcol (No column name)
1 2 1
1 3 1
3 2 1
1 3001 0
MSSQL 방식 : isnull
select a.*,
CASE isnull(b.bcol, 0)
WHEN 0 THEN 0
ELSE 1
END
from testF a
left outer join testZ b
on a.bcol = b.bcol
acol bcol (No column name)
1 2 1
1 3 1
3 2 1
1 3001 0
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