How to round a value to a given decimal place using the ROUND() function?

ROUND(X, D) is a MySQL built-in function that rounds X to decimal place of D. For example:

SELECT ROUND(-1.58), ROUND(23.298, 1), ROUND(23.298, -1);
  -- +--------------+------------------+-------------------+
  -- | ROUND(-1.58) | ROUND(23.298, 1) | ROUND(23.298, -1) |
  -- +--------------+------------------+-------------------+
  -- |           -2 |             23.3 |                20 |
  -- +--------------+------------------+-------------------+

Reference information of the ROUND() function:

ROUND(X, D): val
  Rounds the argument X to D decimal places. D can be negative to cause
  D digits left of the decimal point of the value X to become zero.

Arguments, return value and availability:
  X: Required. The value to be rounded.
  D: Optional. Default is 0. The decimal place to round to.
  val: Return value. The rounded value.
  Available since MySQL 4.0.

Related MySQL functions:

• TRUNCATE() - Truncating to Decimal Place

⇒ SIGN() - Sign of a Number

⇐ RAND() - Random Value Generator

⇑ MySQL Functions on Numeric Values

⇑⇑ MySQL Function References