Inserting a row to a table using query result values from another table

Question

I have a stored procedure:

CREATE PROCEDURE MyProc
(
    @Param1  [datetime],
    @Param2  [nvarchar](20),
    @Param3  [nvarchar](20),
    @Param4  [nvarchar](20),
    @Param5  [nvarchar](20),
)
AS
BEGIN   
INSERT INTO MyTable1
  (
    Field1,
    Field2,
    Field3,
    Field4,
    Field5
  )   
 SELECT         
    @Param1,
    @Param2,
    @Param3,
    Field12,
    'constantValue'         
FROM   MyTable2
WHERE  Field13 = @Param4
END

How could I change the stored proc in order it inserts into the Field5 of MyTable1 not the constantValue but a result of yet another query to MyTable2 with the last parameter ( @Param5 )?
Ie:

FROM   MyTable2
WHERE  Field13 = @Param5

Answer 1

INSERT INTO MyTable1
(
  Field1,
  Field2,
  Field3,
  Field4,
  Field5
)   
SELECT         
    @Param1,
    @Param2,
    @Param3,
    Field12,
    (
         select field_name from MyTable2 where Field13 = @Param5
    )
FROM   
    MyTable2
WHERE 
    Field13 = @Param4
END

Or declare a new variable:

SET @newparam = (SELECT field_name FROM MyTable2 WHERE Field13 = @Param5 )

Then insert this new parameter into the insert statement.

Answer 2

CREATE PROCEDURE MyProc
(
    @Param1  [datetime],
    @Param2  [nvarchar](20),
    @Param3  [nvarchar](20),
    @Param4  [nvarchar](20),
    @Param5  [nvarchar](20),
)
AS
BEGIN   
INSERT INTO MyTable1
  (
    Field1,
    Field2,
    Field3,
    Field4,
    Field5
  )   
 SELECT         
    @Param1,
    @Param2,
    @Param3,
    Field12,
    (SELECT thing_i_care_about FROM MyTable2 WHERE Field13 = @Param5)
FROM   MyTable2
WHERE  Field13 = @Param4
END

Answer 3

Assumes one row from each SELECT

SELECT         
    @Param1, @Param2, @Param3, Tp4.Field12, Tp5.Field12
    NULL        
FROM
   MyTable2 Tp4
   CROSS JOIN
   MyTable2 Tp5
WHERE
   Tp4.Field13 = @Param4 AND Tp4.Field13 = @Param5

The JOIN changes depending on what you expect eg FULL OUTER JOIN .. ON 1=1

If either query returns more than 1 row then:

• in-line sub-query fails
• insert doesn't make sense: what to insert with 4 rows and 3 rows?

Answer 4

It can be accomplish in different ways as below, in both cases I think we should consider a thing that is what if the returned data might be more than one.

a.

INSERT INTO MyTable1
(
 Field1,
 Field2,
 Field3,
 Field4,
 Field5
)   

SELECT         
 @Param1,
 @Param2,
 @Param3,
 Field12,
  (SELECT TOP 1 Column_Name FROM MyTable2 WHERE Field13 = @Param5)
FROM   MyTable2
WHERE  Field13 = @Param4

b.

DECLARE @Field13 VARCHAR(20)
SELECT TOP 1 @Field13  = FROM MyTable2 WHERE Field13 = @Param5

INSERT INTO MyTable1
(
 Field1,
 Field2,
 Field3,
 Field4,
 Field5
)   

SELECT         
 @Param1,
 @Param2,
 @Param3,
 Field12,
 @Field13
FROM   MyTable2
WHERE  Field13 = @Param4

In either cases will be success though "Field13 = @Param5" condition may reveal multiple data but will work on first(TOP 1) data.