Question

I’m trying to select all records from a table “Table1” but I want a new column called “HasException” that contains a “0” or a “1”. “HasException” must be “0” if the count of row matching the current Id from “Table2” is equal to 0, else it returns 1.

Here’s what I’ve done so far, but it doesn’t works:

SELECT *,
CONVERT(bit, (CASE WHEN (SELECT count(Id) FROM Table2 WHERE Table1.Id=Table2.Id) = 0 THEN 0 ELSE 1 END)) AS HasException
FROM Table1

Answer 1

You want to join the tables (and group on ID) before you can compare the two values like this:

SELECT  dbo.Table_1.*,
    CASE WHEN COUNT(dbo.Table_2.ID) = 0 THEN
        0
    ELSE
        1
    END
    AS HasException
FROM         dbo.Table_1 LEFT OUTER JOIN
                      dbo.Table_2 ON dbo.Table_1.ID = dbo.Table_2.ID
GROUP BY dbo.Table_1.ID