ReferenceFunctionsNumeric FunctionsABS本页总览ABSReturns the absolute value of x. SyntaxABS(x)ExamplesSELECT ABS(-5);+---------+| ABS(-5) |+---------+| 5 |+---------+SELECT ABS(-5.5);+-----------+| ABS(-5.5) |+-----------+| 5.5 |+-----------+