Microsoft

# Calculated Table Joins in Power BI Calculated table joins are used to couple two or more tables of data. Common examples include CROSSJOIN, UNION, EXCEPT and INTERSECT.

### Common Use Cases for Calculated Table Joins in Power BI

• Blending or combining data across multiple tables.
• Creating advanced calculations like new vs. returning users or repeat purchase behavior.
• Querying tables to troubleshoot errors or understand connections in a data model.

## CROSSJOIN

CROSSJOIN() Returns a table that contains the cartesian product of the specified tables.

It is a cartesian product of two sets, forming a new set containing all ordered pairs.

= CROSSJOIN(Table, Table, […] ])

Multiple table expressions can be included in a crossjoin.

Examples:

• ‘Dim Product’
• VALUES(‘Fact Sale’[Store ID]) Resulting table contains 12 rows (4*3) and 2 columns (1+1)

Important Points

• Column names must all be different in all table arguments.
• The number of rows returned equals the product of rows in all tables.
• The number of columns returned equals the sum of columns in all tables.

## UNION

UNION() Combines or “stacks” rows from two or more tables sharing the same column structure.

= UNION(Table, Table, […])

Accepts any DAX expression for two (or more) tables with identical column structure.

Examples:

• ‘Table 2021’, ‘Table 2022’
• ‘Table 2021’, DATATABLE() UNION stacks tables together, just like append

Important Points

• All tables must hold the same number of columns.
• Columns are grouped according to their position in their respective tables.
• Column names are determined by the first table expression.
• Duplicate rows are retained.

## EXCEPT

EXCEPT() Returns all rows from the left table which do not appear in the right table.

= EXCEPT(LeftTable, RightTable)

The left and right tables used for join.

(NOTE: The First table must be a table inside the data model.)

Example:

• EXCEPT(‘Dim Product A’​, ‘Dim Product B’) Resulting table contains rows which ONLY appear in the left table

Important Points

• Both tables must hold the same number of columns.
• Columns are compared based on positioning in their respective tables.
• Column names are determined by the left table.
• The resulting table does NOT retain relationships to other tables (can’t be used as an expanded table).

## INTERSECT

INTERSECT() Returns all the rows from the left table which also appear in the right table.

= INTERSECT(LeftTable, RightTable)

The left and right tables used for joining.

(NOTE: The first table must be a table inside the data model.)

Example:

• Previous Month Active Customers =

LeftTable: VALUES(‘Fact Sales’[Customer ID]),
RightTable: CALCULATETABLE( VALUES(​’Fact Sales’[Customer ID]), DATEADD(‘Dim Calendar’[Date],-1, MONTH))

• INTERSECT(‘Dim Product A’, ‘Dim Product B’) Resulting table contains rows which appear in BOTH tables

Important Points

• Order matters! The result of (T1, T2) may be different from (T2, T1).
• Columns are compared based on positioning in their respective tables.
• Duplicate rows are retained.
• Column names are determined by the left table.
• The resulting table does NOT retain relationships to other tables (can’t be used as an expanded table).

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##### Prashant Parkhedkar

Prashant is an Associate Technical Consultant at Perficient in Nagpur. He is a Microsoft Certified Power BI Data Analyst Associate with over 3 years of experience. He is enthusiastic and eager to dive into the world of business analytics.

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