Chapter 1 SQL operators

Chapter one SQL The operator

SQL The operator Symbol (-)

Unary operator that returns an expression as a negative number .

The outline

-expression

Parameters

• expression - Numerical expression .

describe

Unary operators operate on only one expression of any data type of the numeric data type category .

– yes SQL Expand .

Example

The following example returns three numeric fields ： Sample.Person Medium Age Column ; – Age Average （ negative ） value ; And age minus average age ：

SELECT Age,
       -(AVG(age)) AS NegAvg,
       Age-AVG(Age) AS AgeRelAvg
FROM Sample.Person

SQL The operator Symbol (+)

Unary operator that returns an expression as a positive value .

The outline

+expression

Parameters

• expression - Numerical expression .

describe

Unary operators operate on only one expression . This expression can be any data type of the numeric data type category .
+（ just ） It's a SQL Expand .