Syntax
------

-

Description
-----------

Subtraction. The operator is also used as the unary minus for changing sign.

If both operands are integers, the result is calculated with BIGINT precision.
If either integer is unsigned, the result is also an unsigned integer, unless
the NO_UNSIGNED_SUBTRACTION SQL_MODE is enabled, in which case the result is
always signed.

For real or string operands, the operand with the highest precision determines
the result precision.

Examples
--------

SELECT 96-9;
+------+
| 96-9 |
+------+
|   87 |
+------+

SELECT 15-17;
+-------+
| 15-17 |
+-------+
|    -2 |
+-------+

SELECT 3.66 + 1.333;
+--------------+
| 3.66 + 1.333 |
+--------------+
|        4.993 |
+--------------+

Unary minus:

SELECT - (3+5);
+---------+
| - (3+5) |
+---------+
|      -8 |
+---------+

URL: https://mariadb.com/kb/en/subtraction-operator-/