How to use SQL Select statement with IF EXISTS sub query

Question

How to select Boolean value from sub query with IF EXISTS statement  SQL Server    It should be something like    SELECT    TABEL1 Id     NewFiled    IF EXISTS SELECT Id FROM TABLE2 WHERE TABLE2 ID   TABEL1 ID                    SELECT  TRUE                 ELSE                   SELECT  FALSE    FROM TABEL1

User · Answer

Use a CASE statement and do it like this   SELECT      T1 Id  Id       CASE WHEN T2 Id IS NOT NULL THEN  TRUE  ELSE  FALSE  END  Has Foreign Key in T2  FROM     TABLE1  T1      LEFT OUTER JOIN         TABLE2  T2          ON         T2 Id   T1 Id

User · Answer

You can also use ISNULL and a select statement to get this result  SELECT Table1 ID  ISNULL  SELECT  TRUE  FROM TABLE2 WHERE TABLE2 ID   TABEL1 ID   FALSE   AS columName  etc FROM TABLE1

User · Answer

Use CASE   SELECT    TABEL1 Id     CASE WHEN EXISTS  SELECT Id FROM TABLE2 WHERE TABLE2 ID   TABLE1 ID         THEN  TRUE          ELSE  FALSE    END AS NewFiled   FROM TABLE1     If TABLE2 ID is Unique or a Primary Key  you could also use this   SELECT    TABEL1 Id     CASE WHEN TABLE2 ID IS NOT NULL        THEN  TRUE          ELSE  FALSE    END AS NewFiled   FROM TABLE1   LEFT JOIN Table2     ON TABLE2 ID   TABLE1 ID

User · Answer

SELECT Id   TRUE  AS NewFiled FROM TABEL1 INTERSECT SELECT Id   TRUE  AS NewFiled FROM TABEL2 UNION SELECT Id   FALSE  AS NewFiled FROM TABEL1 EXCEPT SELECT Id   FALSE  AS NewFiled FROM TABEL2

[sql] How to use SQL Select statement with IF EXISTS sub query?

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