UNION

Stacks the rows of two or more tables with the same number of columns, duplicates included.

Group: Table manipulation. Compatible with DAX.

Syntax

UNION ( <table_expression1>, <table_expression2> [, <table_expression>] … )

Parameter	Type	Description
`table_expression1`	Table	The first table; its column names are the result's.
`table_expression2`	Table	The second table, with as many columns as the first.
`table_expression`	Table optional, repeatable	Further tables, again with as many columns.

Returns

Table. The rows of all the tables, one table after another, under the first table's column names.

Remarks

Columns are matched by position: each table's first column goes into the first column of the result, whatever its name. A different number of columns is an error.
Duplicates are not removed. Wrap it in DISTINCT to get each row once.
When one table's column is text and another's holds numbers or dates, the column becomes text: a whole number and a text give text. When none is text but one holds values of different kinds, such as IFERROR ( x, "error" ) or an IF that gives a number or a text, each value keeps its own type.
A column stays tied to the model only when it comes from the same model column in every table; otherwise it holds plain values.

Examples

Two lists of shops

Frogner is in both and appears twice. The second table's column names do not matter.

EVALUATE
VAR Oslo =
    DATATABLE ( "Shop", STRING, "Liters", INTEGER, { { "Frogner", 120 }, { "Storo", 80 } } )
VAR Bergen =
    DATATABLE ( "Name", STRING, "Volume", INTEGER, { { "Bryggen", 95 }, { "Frogner", 120 } } )
RETURN
    UNION ( Oslo, Bergen )
ORDER BY [Shop]

Shop	Liters
Bryggen	95
Frogner	120
Frogner	120
Storo	80

A number and a text in one column

EVALUATE
VAR Numbers = DATATABLE ( "Code", INTEGER, { { 1 } } )
VAR Texts = DATATABLE ( "Code", STRING, { { "x" } } )
RETURN
    UNION ( Numbers, Texts )
ORDER BY [Code]

Code
1
x

A union of the same column filters it

EVALUATE
ROW (
    "Pils and IPA",
        CALCULATE (
            [Liters sold],
            UNION (
                FILTER ( VALUES ( Products[Product] ), Products[Product] = "Pils" ),
                FILTER ( VALUES ( Products[Product] ), Products[Product] = "IPA" )
            )
        )
)

Pils and IPA
1336210

EXCEPT, INTERSECT, DISTINCT, DATATABLE, ROW.

Last updated 3 November 2026 · OpenBI Studio 0.3.74