Logical Functions in DAX

Logical Functions in DAX

  June 20, 2023    asghars

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• Logical functions evaluates to TRUE or FALSE.
• Following are the DAX Logical functions.
• IF(logical_test, result_true, result_false) 
• Evaluates a condition and returns one value if it is TRUE, and another value if it is FALSE.

• The IF logical function can also be nested. 

• IF.EAGER(logical_test, result_true, result_false)
• IF.EAGER logical function like IF function evaluates a condition and returns one value if it is TRUE, and another value if it is FALSE.
• F.EAGER has the same functional behavior as the IF function, but performance may differ due to differences in execution plans as it uses an eager execution plan.
• The IF function is strictly evaluated while IF.EAGER is eagerly evaluated.
• For example in IF (2<1, 1+2, 4+1), Power BI will only compute the second part (4+1) since the condition 2<1 is false, and the first part (1+2) will not be computed.
• While in IF.EAGER (2<1, 1+2, 4+1) both true and false parts will be evaluated.
• In cases where true and false parts are computed the IF.EAGER provides a better performance as compared to IF function.

• SWITCH(expression, option1, result1, option2, result2,                  ............, elseResult)
• Switch logical function evaluates an expression against a list of values and return the one of possible results.

• By default SWITCH function checks for equality, to achieve functionality of other operators like less than or greater than we can replace expression with TRUE() function.
• By using TRUE() now Switch will be checking the subsequent options/conditions for true.

• AND(logical_val_1, logical_val_2)
• AND logical function returns TRUE if both the arguments are TRUE otherwise returns FALSE.
• The AND function operates similarly to the && logical operator.

• OR(logical_val_1, logical_val_2)
• OR logical function returns TRUE if one of the arguments is TRUE, otherwise returns FALSE.
• The OR function operates similarly to the || logical operator.

• NOT(logical_val)
• NOT logical function inverts FALSE to TRUE or TRUE to FALSE.

• COALESCE(val1, val2, val3, ........)
• COALESCE logical function accepts multiple arguments and returns the first non-blank argument. If the first argument is blank, it returns the value from the second argument, and so on. If all arguments are blank, it returns blank.

• IFERROR(expression, val_if_error) 
• IFERROR logical function returns val_if_error if error occurs during evaluation of expression, otherwise it returns value of expression. 

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