Select Sum of Column Values with Higher Value in Each Row with MySQL

Use the CASE statements and set conditions for the same. Let us first create a table −

mysql> create table DemoTable
   -> (
   -> X int,
   -> Y int
   -> );
Query OK, 0 rows affected (0.57 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable values(20,30);
Query OK, 1 row affected (0.15 sec)

mysql> insert into DemoTable values(40,15);
Query OK, 1 row affected (0.14 sec)

mysql> insert into DemoTable values(80,85);
Query OK, 1 row affected (0.13 sec)

Display all records from the table using select statement −

mysql> select *from DemoTable;

Output

This will produce the following output −

+------+------+
| X    | Y    |
+------+------+
|   20 |   30 |
|   40 |   15 |
|   80 |   85 |
+------+------+
3 rows in set (0.00 sec)

Following is the query to select the sum of the column values with higher value in each row.

mysql> SELECT SUM(CASE WHEN X > Y THEN X ELSE Y END) from DemoTable;

Output

This will produce the following output −

+----------------------------------------+
| SUM(CASE WHEN X > Y THEN X ELSE Y END) |
+----------------------------------------+
|                                    155 |
+----------------------------------------+
1 row in set (0.00 sec)