Set Operators in Qlikview
There are several set operators that can be used in set expressions. All set operators use sets as operands and return a set as result.
+ (Union): This binary operation returns a set consisting of the records that belong to any of the two set operands.
– (Exclusion): This binary operation returns a set of the records that belong to the first but not the other of the two set operands. Also, when used as a unary operator, it returns the complement set.
* (Intersection): This binary operation returns a set consisting of the records that belong to both of the two set operands.
/ (Symmetric difference): This binary operation returns a set consisting of the records that belong to either, but not both of the two set operands.
The order of precedence is:
- Unary minus (complement)
- Intersection and Symmetric difference
- Union and Exclusion
Within a group, the expression is evaluated from left to right. Alternative orders can be defined by standard brackets, which may be necessary because the set operators do not commute.
For example, A+(B-C) is different from (A+B)-C which in turn is different from (A-C)+B.