Question

two tables in database, similar structure below.

-I need the list of elements from TABLE1 where P1 matches S3 and at the same time P2 matches S2.

+            TABLE1           +        +           TABLE2            +
+---------+---------+---------+        +---------+---------+---------+
| P1      | P2      | P3      |        + S1      | S2      | S3      |
+---------+---------+---------+        +---------+---------+---------+
| A       | B       | C       |        | P       | B       | A       |
| B       | B       | C       |        | A       | G       | T       |
| Z       | K       | R       |        | T       | M       | T       |
| T       | S       | L       |        | M       | K       | Z       |
| W       | W       | W       |        | W       | W       | W       |
+---------+---------+---------+        +---------+---------+---------+

so, as a result I shall get:

+            RESULT           +
+---------+---------+---------+
| P1      | P2      | P3      |
+---------+---------+---------+
| A       | B       | C       |
| Z       | K       | R       |
| W       | W       | W       |
+---------+---------+---------+

the question : what is the oracle query that does this join, compare and match operations.
Note: using a loop is discouraged.

Thanks in advance…

Answer 1

You can use INNER JOIN to combine both tables.

SELECT  a.*
FROM    table1 a
        INNER JOIN table2 b
            ON a.P1 = b.S3 AND
               a.P2 = b.S2

CLICK here for more type of Joins (Oracle Docs)