tsql - SQL Server check resultant data type of expression

Question

Normally I would put the data type into a temp table and inspect the table column type, e.g.

select 1.0 N into tbl

sp_help tbl

Column N then reveals the data type of the expression 1.0. (This is a only simple example)

There is a SQL function to inspect the data type of an expression directly, but the name escapes me right now.

What is the name of this function?

Answer 1

SQL_VARIANT_PROPERTY is close

DECLARE @what sql_variant;
DECLARE @foo decimal(19,3) = 1, @bar decimal(11,7) = 2;

SELECT @what = @foo / @bar;
SELECT
    SQL_VARIANT_PROPERTY(@what, 'BaseType'),
    SQL_VARIANT_PROPERTY(@what, 'Precision'),
    SQL_VARIANT_PROPERTY(@what, 'Scale'),
    SQL_VARIANT_PROPERTY(@what, 'MaxLength');

SELECT @what = @foo + @bar;
SELECT
    SQL_VARIANT_PROPERTY(@what, 'BaseType'),
    SQL_VARIANT_PROPERTY(@what, 'Precision'),
    SQL_VARIANT_PROPERTY(@what, 'Scale'),
    SQL_VARIANT_PROPERTY(@what, 'MaxLength');


SELECT @what = @foo * @bar;
SELECT
    SQL_VARIANT_PROPERTY(@what, 'BaseType'),
    SQL_VARIANT_PROPERTY(@what, 'Precision'),
    SQL_VARIANT_PROPERTY(@what, 'Scale'),
    SQL_VARIANT_PROPERTY(@what, 'MaxLength');

Or temp table/SELECT..INTO.. as an extension of what you've already done

Edit: Remus' answer?