Passing a Scalar reference into another Scalar

Question

In SQL Server, I have a stored procedure that accepts a date parameter. That date paramater is then passed along to another stored procedure. However, the 2nd stored procedure parameter is named as the first parameter. and then I need to I have 2 different scalar variables:

DECLARE @date date, @sql varchar(100);

SET @date = '2012-07-01';
SELECT @sql = ('EXEC pStoredprocedure @date = '''+@date+'''')

I need the @sql scalar to contain this text so the stored procedure can call the other stored procedure:

EXEC pStoredprocedure @date = '2012-07-01'

But, when I run my code above, I get this error:

Msg 402, Level 16, State 1, Line 4 The data types varchar and date are incompatible in the add operator.

It's almost like I need to escape the @date operator. Can this be done?

Side note: Yes, I'm trying to dynamically pass along some variables. I understand the dangers of doing so, but doing it this way is much simpler...

Answer 1

The date variable is being used in string concatenation, so it should be treated as a string, either through its declaration, a convert function, or a cast. I tried this:

 DECLARE @date varchar(20), @sql varchar(100);
SET @date = '2012-07-01';
SELECT @sql = ('EXEC pStoredprocedure @date = ''' + @date + '''')

 PRINT @sql

and got this:

 EXEC pStoredprocedure @date = '2012-07-01'

I am stuck on 2005, so I don't have the date datatype, but when I tried to use datetime, I got this error:

Msg 241, Level 16, State 1, Line 4 Conversion failed when converting datetime from character string.

You can also try

 DECLARE @date datetime, @sql varchar(100);
SET @date = '2012-07-01';
SELECT @sql = ('EXEC pStoredprocedure @date = ''' + CONVERT(varchar(20), @date, 102) + '''')
 PRINT @SQL;

and get

 EXEC pStoredprocedure @date = '2012.07.01'