Below is a part of my select query. In the same query I am selecting COLUMN_1 from a table TABLE2 with condition check. Also I am joining this table at end with one of the condition in the inner select as below. Can we have any other way to handle this situation with out using multiple `SELECT inside.
SELECT
T1.COLUMN_1
, (SELECT COLUMN_1 FROM TABLE2 WHERE COLUMN_22 ='A' AND COLUMN_11=T2.COLUMN_11)
, T1.COLUMN_2
, (SELECT COLUMN_1 FROM TABLE2 WHERE COLUMN_22 ='B' AND COLUMN_11=T2.COLUMN_11)
, T1.COLUMN_3
, (SELECT COLUMN_1 FROM TABLE2 WHERE COLUMN_22 ='C' AND COLUMN_11=T2.COLUMN_11)
, T1.COLUMN_4
, (SELECT COLUMN_1 FROM TABLE2 WHERE COLUMN_22 ='D' AND COLUMN_11=T2.COLUMN_11)
, T1.COLUMN_5
, (SELECT COLUMN_1 FROM TABLE2 WHERE COLUMN_22 ='E' AND COLUMN_11=T2.COLUMN_11)
, T1.COLUMN_6
, (SELECT COLUMN_1 FROM TABLE2 WHERE COLUMN_22 ='F' AND COLUMN_11=T2.COLUMN_11)
FROM TABLE1 T1, TABLE2 T2
-- plus two more tables
--plus some other conditions
WHERE T1.COLUMN_11=T2.COLUMN_11
Use CASE instead:
SELECT T1.COLUMN_1
,CASE
WHEN T2.COLUMN_22 = 'A'
THEN T2.COLUMN_1
END
,T1.COLUMN_2
,CASE
WHEN T2.COLUMN_22 = 'B'
THEN T2.COLUMN_1
END
,T1.COLUMN_3
,CASE
WHEN T2.COLUMN_22 = 'C'
THEN T2.COLUMN_1
END
,T1.COLUMN_4
,CASE
WHEN T2.COLUMN_22 = 'D'
THEN T2.COLUMN_1
END
,T1.COLUMN_5
,CASE
WHEN T2.COLUMN_22 = 'E'
THEN T2.COLUMN_1
END
,T1.COLUMN_6
,CASE
WHEN T2.COLUMN_22 = 'F'
THEN T2.COLUMN_1
END
FROM TABLE1 T1
INNER JOIN TABLE2 T2 ON T1.COLUMN_11 = T2.COLUMN_11;
EDIT
I changed the query to use the ansi join syntax. But that change is irrelevant to what you are asking. You can keep your join syntax if you want. The only relevant change is in the SELECT portion of the query.
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