DAX stands for Data Analysis Expressions and is the language used by PowerBI to create calculations. The syntax is quite different to SQL and involves a lot of brackets and commas.
Below are three examples that show two different ways the same output can be achieved using DAX:
AND( ) vs &&
The below example will find the products that are items of clothing and are less than £30.
IF (AND (Table[Price]<30, Table[Category] = "Clothing"), "Sale Item", "Regular Item")
IF (Table[Price]<30 && Table[Category]="Clothing", "Sale Item", "Regular Item")
MONTH( ) vs .[MonthNo]
Both expressions below will return the month number of the date with .[MonthNo] removing the need for brackets entirely.
MONTH (Table[Date])
Table[Date].[MonthNo]
Nested IF functions vs SWITCH( )
The SWITCH function reduces the need for multiple IF functions where a missing bracket can easily break the function.
IF (Table[Price]<10, "Low", IF(Table[Price]<30, "Medium","High"))
SWITCH (TRUE( ), Table[Price]<10, "Low", Table[Price]<30, "Medium", "High")
