DAX function
UNION — DAX function reference
Stack rows from tables.
Syntax
dax
UNION(<table1>, <table2> [, …])
Examples
dax
UNION(Actuals, Budget)
→ A table
dax
UNION(VALUES(Actuals[Region]), VALUES(Budget[Region]))
→ Every region that appears in either table, including duplicates if a region is in both
Wrap UNION in DISTINCT when you need true set-union semantics.
dax
DISTINCT(UNION(VALUES(Actuals[Region]), VALUES(Budget[Region])))
→ Deduplicated combined region list
Common mistakes & gotchas
- UNION combines rows by column position, not column name — all tables must have the same number of columns, and mismatched data types in the same position can cause an error or an unwanted implicit conversion.
- UNION doesn't remove duplicates by itself (it's really an append) — wrap it in DISTINCT if you need actual set-union semantics rather than a simple stack of rows.
Related DAX functions
From Tables & set operations