Q:
SQL - Pass the result of the first query as the second query select column name
I want to pass the result of a sql query as the column name in another query eg. (note there will be a single result for the first query)
SELECT
CASE
WHEN fld_type1 = 'A' THEN 'VAL_ALPHA1'
WHEN fld_type1 = 'D' THEN 'VAL_DATE1'
ELSE 'VAL_NUM1'
END AS FIELDNAME
FROM TABLE1
I want the result of the first query to pass to the second query as the select column name
SELECT <1st Query Result>
FROM TABLE2
WHERE ID = 8
SELECT
CASE
WHEN fld_type1 = 'A' THEN 'VAL_ALPHA1'
WHEN fld_type1 = 'D' THEN 'VAL_DATE1'
ELSE 'VAL_NUM1'
END AS FIELDNAME
FROM TABLE1
I want the result of the first query to pass to the second query as the select column name
SELECT <1st Query Result>
FROM TABLE2
WHERE ID = 8
ASKED:
Mar 24 2009 11:07 AM GMT
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
A:
RATE THIS ANSWER
+1
Click to Vote:
+1
Click to Vote:
- 1
0
What database are you using ? what version ?
In Sql Server, this would be one way to do it:
DECLARE @selectStmt nvarchar(4000),
@field nvarchar(100)
SELECT @field =
CASE
WHEN fld_type1 = 'A' THEN 'VAL_ALPHA1'
WHEN fld_type1 = 'D' THEN 'VAL_DATE1'
ELSE 'VAL_NUM1'
END
FROM table1
SET @selectStmt = 'SELECT '+@field+' FROM table2 WHERE id = 8'
EXEC(@selectStmt);
GO
Beware that dynamic SQL pose some security issues.
Have a look at the following article to read more about Dynamic SQL:
The Curse and Blessings of Dynamic SQL
