A comparison operator is a binary operator that takes two expressions as operands. The expressions must both be numeric, character (any of the four character types), money or date types. The following operators are recognized in QUEL:

All comparison operators are of equal precedence. When comparisons are made between c strings or between a c string and a string of any of the other types, all blanks are ignored. When comparisons are made between text, char, or varchar strings, all blanks are significant.

Nullable and non-nullable data types can be compared. If one or both of the values is null, the comparison returns the value unknown.