DAX Formulas and Functions Flashcards

What is the purpose of the VAR keyword in DAX?

Answer: To declare a variable and store an expression result for reuse within a formula

VAR declares a named variable within a DAX expression, storing an intermediate result to improve readability and avoid repeated computation.

Which DAX function returns a table of unique values from a column?

Answer: DISTINCT

DISTINCT returns a one-column table of unique values from a specified column, excluding duplicates but not blank.

What does the SWITCH function do in DAX?

Answer: Evaluates an expression against a list of values and returns the corresponding result

SWITCH evaluates an expression, compares it to a list of values, and returns the result associated with the first match, similar to a CASE statement.

What is the difference between SUMX and SUM in DAX?

Answer: SUMX iterates a table row by row using an expression; SUM aggregates a single column directly

SUMX iterates each row of a table, evaluates an expression per row, and sums the results, while SUM simply totals a column's values.

What does BLANK() represent in DAX?

Answer: A null/missing value that propagates through calculations

BLANK() represents the absence of a value (similar to NULL), and most DAX functions treat blank as zero in arithmetic but as missing in text operations.

Which DAX function is used to move calculations to a previous time period?

Answer: SAMEPERIODLASTYEAR

SAMEPERIODLASTYEAR returns a table of dates shifted back exactly one year, enabling year-over-year comparisons.