如何将查询的不同结果从一个表连接到存储过程中的另一个表

Question

I have tree tables:

1. Products (Fields: Reference, ...)
2. InvoiceHeader (Fields: In_No,In-Date,Type, ...)
3. InvoiceDetails (Reference, Qty, ...)

I want to write a stored procedure which return all the references with the Stock of them.

Invoices are two types: input (which add to stock) and output (which subtract from stock).

It means I have to run a query for two times on InvoiceHeader joining InvoiceDetails on for having inputs of all the references and one for having outputs of the references.

Then I have to join these two queries to the products and make a new field (remain) which minus output from input for each reference.

The results should be like this:

Reference   Input   Output   Remain  
X             5        2        3
Y            10        3        7
Z             1        1        0

How can I write the procedure?

Answer 1

Could you please precise what do you would like to know? How to pass 3 values to output, select 3 values, or 'do the job' inside the procedure?

SQL server supports having more than one output value. So If that is your issue you can use for example that blog post which describes how to do that. If your goal is to have procedure which selects these values, but they will not be used in the future you can just... select them in the procedure body... as per below

 create procedure as X
    begin
      select ...
      select ...
      select ...  
    end 

Answer 2

You can write a procedure with table result set output, like this:

CREATE PROCEDURE my_stored_proc
    @param1     INT,
    @param2     INT
AS
BEGIN
    SELECT  T.field1,
            T.field2
    FROM    my_table    AS  T
    WHERE   T.field3    =   @param1
    AND     T.field4    =   @param2
END

so when executing the procedure, you'd get the result same as executing SELECT statement.

In sql-server (mssql) you can "collect" the output result-set like this:

DECLARE @output1 AS TABLE (field1 INT, field2 INT)
INSERT INTO @output1
EXEC my_stored_proc @param1 = 1, @param2 = 2

you can then use the collected output with any other query, like this:

SELECT  T.field2 * 2 + T.field1
FROM    @output1    AS  T
JOIN    some_table6 AS  T6  ON  T6.id = T.field1