SQL Operators

Operator Precedence

SQL Operators are divided into four types.Each operator type has a precedence, a ranking that determines the order in which operators and the values obtained with their help are evaluated in an expression.The higher the precedence of the operator type is, the earlier it will be evaluated.Each operator has its own precedence within its type, that determines the order in which they are evaluated in an expression.

Operators with the same precedence are evaluated from left to right.To force a different evaluation order, operations can be grouped by means of parentheses.

Table 1. Operator Type Precedence
Operator Type	Precedence	Explanation
Concatenation	1	Strings are concatenated before any other operations take place
Arithmetic	2	Arithmetic operations are performed after strings are concatenated, but before comparison and logical operations
Comparison	3	Comparison operations take place after string concatenation and arithmetic operations, but before logical operations
Logical	4	Logical operators are executed after all other types of operators