When MySQL stores a value in a numeric column that is outside the permissible range of the column data type, the result depends on the SQL mode in effect at the time:

If strict SQL mode is enabled, MySQL rejects the out-of-range value with an error, and the insert fails, in accordance with the SQL standard.

If no restrictive modes are enabled, MySQL clips the value to the appropriate endpoint of the range and stores the resulting value instead.

When an out-of-range value is assigned to an integer column, MySQL stores the value representing the corresponding endpoint of the column data type range. If you store 256 into a

`TINYINT`

or`TINYINT UNSIGNED`

column, MySQL stores 127 or 255, respectively.When a floating-point or fixed-point column is assigned a value that exceeds the range implied by the specified (or default) precision and scale, MySQL stores the value representing the corresponding endpoint of that range.

Column-assignment conversions that occur due to clipping when
MySQL is not operating in strict mode are reported as warnings
for `ALTER TABLE`

,
```
LOAD DATA
INFILE
```

, `UPDATE`

, and
multiple-row `INSERT`

statements.
In strict mode, these statements fail, and some or all the
values will not be inserted or changed, depending on whether the
table is a transactional table and other factors. For details,
see Section 5.1.7, “Server SQL Modes”.

In MySQL 5.0, overflow handling during numeric expression evaluation depends on the types of the operands:

Integer overflow results in silent wraparound.

`DECIMAL`

overflow results in a truncated result and a warning.Floating-point overflow produces a

`NULL`

result. Overflow for some operations can result in`+INF`

,`-INF`

, or`NaN`

.

For example, the largest signed
`BIGINT`

value is
9223372036854775807, so the following expression wraps around to
the minimum `BIGINT`

value:

mysql>+-------------------------+ | 9223372036854775807 + 1 | +-------------------------+ | -9223372036854775808 | +-------------------------+`SELECT 9223372036854775807 + 1;`

To enable the operation to succeed in this case, convert the value to unsigned;

mysql>+-------------------------------------------+ | CAST(9223372036854775807 AS UNSIGNED) + 1 | +-------------------------------------------+ | 9223372036854775808 | +-------------------------------------------+`SELECT CAST(9223372036854775807 AS UNSIGNED) + 1;`

Whether overflow occurs depends on the range of the operands, so
another way to handle the preceding expression is to use
exact-value arithmetic because
`DECIMAL`

values have a larger
range than integers:

mysql>+---------------------------+ | 9223372036854775807.0 + 1 | +---------------------------+ | 9223372036854775808.0 | +---------------------------+`SELECT 9223372036854775807.0 + 1;`

Subtraction between integer values, where one is of type
`UNSIGNED`

, produces an unsigned result by
default. If the result would otherwise have been negative, it
becomes the maximum integer value. If the
`NO_UNSIGNED_SUBTRACTION`

SQL
mode is enabled, the result is negative.

mysql>mysql>`SET sql_mode = '';`

+-------------------------+ | CAST(0 AS UNSIGNED) - 1 | +-------------------------+ | 18446744073709551615 | +-------------------------+ mysql>`SELECT CAST(0 AS UNSIGNED) - 1;`

mysql>`SET sql_mode = 'NO_UNSIGNED_SUBTRACTION';`

+-------------------------+ | CAST(0 AS UNSIGNED) - 1 | +-------------------------+ | -1 | +-------------------------+`SELECT CAST(0 AS UNSIGNED) - 1;`

If the result of such an operation is used to update an
`UNSIGNED`

integer column, the result is
clipped to the maximum value for the column type, or clipped to
0 if `NO_UNSIGNED_SUBTRACTION`

is enabled. If strict SQL mode is enabled, an error occurs and
the column remains unchanged.