## Introduction

Data Analysis Expressions (DAX) is used to compute the data in the power BI. DAX can be used to create measure as well as calculated column. It is not a programming language; it is a formula as well as query language. If you unleash the power of DAX, then you can become a power BI expert.

In this article, we are going to see the 15 DAX functions mostly used by powerbi developers with its syntax.

## What is Measure?

Measure is an aggregated output value created in power BI by using different pre-defined functions as well as user defined functions. It will be calculated dynamically based on the column used with it.

## What is expression?

A sequence of operands and operators is called an **expression.**

**Eg**: [unit price] * [quantity] – [discount]. Here unit price, Quantity and discount are operands and *,- are operator.

## Content:

DAX can be used to create measure as well as calculated column. In here among 15 DAX first 8 will be measures and the remaining 7 are calculated column/table.

- SUM
- AVERAGE
- MIN
- MAX
- CALCULATE
- COUNT/DISTINCTCOUNT
- COUNTROWS
- DISTINCT
- FILTER
- PREVIOUSDAY
- DATEDIFF
- CALENDAR
- RELATED
- TOTALYTD
- CALCULATETABLE

*SUM*

The sum function adds the value in the column of a table. The syntax is given below:

**SUM** (column name)

*AVERAGE*

The average function gives the average value of a column from the table. The syntax is given below:

**AVERAGE** (column name)

*MIN*

The Min function finds the minimum value in a column or minimum value between two expressions. The syntax is given below.

**MIN**(columnname), **MIN**(expression1, expression2)

*MAX*

The Max function finds the maximum value in a column or maximum value between two expressions. The syntax is given below.

**MAX**(columnname), **MAX**(expression1, expression2)

*CALCULATE*

The calculate function used to compute complex functions with the conditions mentioned in the filter variable. User can add as many filter as they need. The syntax is given below. **CALCULATE**(expression, filter1,filter2,…)

*COUNT*

The count function used to count the number of values in a column. Null values are not included The syntax is given below:

**COUNT**(column name)

*COUNTROWS*

The count rows function returns the number of rows in the given table. The syntax is given below:

**COUNTROWS**(table name)

*DISTINCT*

1. The function distinct can be used on column as well as table. It will return a one column distinct table or distinct row table. The syntax for count function is given below:

**DISTINCT**(column name), **DISTINCT**(table name)

*FILTER*

The count function used to count the number of values in a column. Null values are not included The syntax is given below:

**COUNT**(column name)

### P*REVIOUSDAY*

This function returns a column that contains previous day of each value. The syntax is given below:

**PREVIOUSDAY**(date column)

*DATEDIFF*

This function returns the date difference in number based on the interval given. The syntax is given below:

**DATEDIFF**(start date, end date, interval)

*CALENDAR*

This function returns the one column table with date as column name. The range of dates is taken from start date and end date. The syntax is given below:

**CALENDAR**(start date, end date)

*RELATED*

This function returns related column value from another table based on the relationship mentioned between the tables. The syntax is given below:

**RELATED**(column name)

*TOTALYTD*

This function returns the aggregated output based on the dates passed and the output is filtered on current year to today’s date. The syntax is given below:

**TOTALYTD**(expression, dates)

*CALCULATETABLE*

This function returns table of values with filters applied on it. The syntax is given below:

**CALCULATETABLE**( expression,filter1,filter2,…)

Most of the functions have been used in the sample power BI report provided in the Microsoft website. Check it out using the below link. click here