从存储过程中从存储过程中的 SELECT 语句获取标量值

Question

I know the preferred method for returning scalar values from stored procs is either using RETURN or an OUTPUT parameter. But lets say that I have a stored proc that returns the value using a select statement:

CREATE PROC spReturnNumber AS

SELECT 1

Is it possible to get this value from within another stored proc?

CREATE PROC spCheckNumber AS

EXEC spReturnNumber -- <-- get the return value here?

Clarification: I need a solution that doesn't require using an OUTPUT parameter, or using RETURN to return the value.

Thanks in advance.

Answer 1

You could use insert-exec to store the result of a stored procedure in a table:

declare @t table (col1 int)
insert @t exec spReturnNumber
return (select col1 from @t)

The definition of the table has to match the result set of the stored procedure.

Answer 2

Use an OUTPUT parameter instead of (or in addition to, if this procedure is used by other applications) the SELECT .

ALTER PROCEDURE dbo.spReturnNumber
    @Number INT OUTPUT
AS
BEGIN
    SET NOCOUNT ON;

    SET @Number = 1;
    SELECT @Number;
END
GO

CREATE PROCEDURE dbo.spCheckNumber
AS
BEGIN
    SET NOCOUNT ON;

    DECLARE @Number INT;
    EXEC dbo.spReturnNumber @Number = @Number;
    SELECT @Number;
END
GO

If you can't change the original procedure, but you know its output will remain static, you could use a #temp table.

CREATE PROCEDURE dbo.spCheckNumber
AS
BEGIN
    SET NOCOUNT ON;

    CREATE TABLE #n(i INT);
    INSERT #n(i) EXEC dbo.spReturnNumber;

    DECLARE @Number INT;
    SELECT @Number = i FROM #n;
END
GO

Answer 3

You can't get the SELECT value from "parent" procedure but you can get the return value like this:

CREATE PROC A AS
BEGIN
    DECLARE @ret int

    EXEC @ret = spReturnNumber

    RETURN @ret
END

Answer 4

Per OP's request, the PostgreSQL way to do this. The first function, foo() just returns an INT. The following functions, bar() and baz() call foo() , in straight SQL, as well as in PL/pgSQL, respectively.

CREATE FUNCTION foo() RETURNS INT AS $$
    SELECT 1
$$ LANGUAGE sql;

CREATE FUNCTION bar() RETURNS INT AS $$
    SELECT foo()
$$ LANGUAGE sql;

CREATE FUNCTION baz() RETURNS INT AS $$
DECLARE
    x INT;
BEGIN
    SELECT INTO x foo();
    RETURN x;
END
$$ LANGUAGE plpgsql;

db=# SELECT foo();
foo
-----
1
(1 row)

db=# SELECT bar();
bar
-----
1
(1 row)

db=# select baz();
baz
-----
1
(1 row)

Answer 5

If you are unable to change the proc being called.. place the result set in a temp table [or table variable]:

CREATE TABLE #results (val INT)
   DECLARE @someval int
   INSERT #results
     EXEC dbo.spCheckNumber 

   SELECT @someval =val from  #results