If I understand you correctly, you have two columns in Table_1 and two columns in Table_2, both with the same data types. You want to combine these into a single data set, then insert the result into Table_3.
You can approach this by first creating a
SELECT
statement to get the single data set from the two tables. You can do this with a
UNION
:
SELECT Coll AS Column_A, Col2 AS Column_B
FROM Table_1
UNION
SELECT Col3 AS Column_A, Col4 AS Column_B
FROM Table_2
This will return a data set with two columns, populated by the intersection of data from the two tables. That is to say, each row will be distinct. If you need to get any duplicates, instead use
UNION ALL
You do not need to alias the column names, but if the same position (say, Col1 and Col3) have different names in the different tables, the resulting column in the data set will not have any name.
The second step is to use this for your insert. The result might look like this:
INSERT INTO Prod_Confirm (Serial, Group) (
SELECT Col1 AS Serial, Col2 AS Group FROM Table_1
UNION
SELECT Col3 AS Serial, Col2 AS Group FROM Table_2
)
SQL will run the selection, then use the resulting data set for the insert.