MySQL Cast NULL to integer 0

You'd probably want to use the COALESCE() function:

SELECT COALESCE(col, 0) FROM `table`;

COALESCE() returns the first non-NULL value in the list, or NULL if there are no non-NULL values.

Test case:

CREATE TABLE `table` (id int, col int);INSERT INTO `table` VALUES (1, 100);INSERT INTO `table` VALUES (2, NULL);INSERT INTO `table` VALUES (3, 300);INSERT INTO `table` VALUES (4, NULL);

Result:

+------------------+| COALESCE(col, 0) |+------------------+|              100 ||                0 ||              300 ||                0 |+------------------+4 rows in set (0.00 sec)

You can also use the IFNULL() function:

SELECT IFNULL(col, 0) FROM `table`;

IFNULL(expr1, expr2) returns the first expression if it's not null, else returns the second expression.

Test case:

CREATE TABLE `table` (id int, col int);INSERT INTO `table` VALUES (1, 100);INSERT INTO `table` VALUES (2, NULL);INSERT INTO `table` VALUES (3, 300);INSERT INTO `table` VALUES (4, NULL);

Result:

+----------------+| IFNULL(col, 0) |+----------------+|            100 ||              0 ||            300 ||              0 |+----------------+4 rows in set (0.00 sec)