<= (Less Than or Equal To)
Compares two expressions (a comparison operator). When you compare nonnull expressions, the result is TRUE if the left operand has a lower or equal value than the right operand; otherwise, the result is FALSE. If either or both operands are NULL and SET ANSI_NULLS is set to ON, the result is NULL. If SET ANSI_NULLS is set to OFF, the result is FALSE if one of the operands is NULL, and TRUE if both operands are NULL.
expression = < expression
Is any valid Microsoft® SQL Server™ expression. Both expressions must have implicitly convertible data types. The conversion depends on the rules of data type precedence. For more information, see Data Type Precedence.
Operators (Comparison Operators)