# ROUND

## round​

### description​

#### Syntax​

`T round(T x[, d])``x`四舍五入后保留d位小数，d默认为0。如果d为负数，则小数点左边d位为0。如果x或d为null，返回null。 2.5会舍入到3，如果想要舍入到2的算法，请使用round_bankers函数。

### example​

``mysql> select round(2.4);+------------+| round(2.4) |+------------+|          2 |+------------+mysql> select round(2.5);+------------+| round(2.5) |+------------+|          3 |+------------+mysql> select round(-3.4);+-------------+| round(-3.4) |+-------------+|          -3 |+-------------+mysql> select round(-3.5);+-------------+| round(-3.5) |+-------------+|          -4 |+-------------+mysql> select round(1667.2725, 2);+---------------------+| round(1667.2725, 2) |+---------------------+|             1667.27 |+---------------------+mysql> select round(1667.2725, -2);+----------------------+| round(1667.2725, -2) |+----------------------+|                 1700 |+----------------------+mysql> SELECT number    -> , round(number * 2.5, number - 1) AS r_decimal_column    -> , round(number * 2.5, 0) AS r_decimal_literal    -> , round(cast(number * 2.5 AS DOUBLE), number - 1) AS r_double_column    -> , round(cast(number * 2.5 AS DOUBLE), 0) AS r_double_literal    -> FROM test_enhanced_round    -> WHERE rid = 1;+--------+------------------+-------------------+-----------------+------------------+| number | r_decimal_column | r_decimal_literal | r_double_column | r_double_literal |+--------+------------------+-------------------+-----------------+------------------+|      1 |              3.0 |                 3 |               3 |                3 |+--------+------------------+-------------------+-----------------+------------------+``

### keywords​

``ROUND, DROUND``