Data Type is a classification of data which tells compiler or interpreter what type of data is being used.

Data types in Power BI are used to classify values in a particular column which helps us to structure our data set.

Power BI or Power Query shows the data type on the left side of the field name/column name of the table. As shown in the Image below.

Let’s Learn About the Different Data Types in Power BI.

Data type	Description
Any	Indicates no explicit data type definition.
Binary	A binary value, such as Y/N or 0/1.
Fixed decimal number	Has a fixed format of four digits to the right and 19 digits to the left. Also known as the Currency type.
Date	A date with no time and having a zero for the fractional value.
Date/Time	A date and time value stored as a Decimal Number type.
Date/Time/Time Zone	A UTC Date/Time with a time-zone offset.
Duration	A length of time converted into a Decimal Number.
True/False	A Boolean value of either True or False.
Decimal number	A 64-bit (eight-byte) floating point number.
Percentage	A fixed decimal number with a mask to format as a percentage.
Text	Strings, numbers, or dates represented in a text format.
Time	A time with no date having no digits to the left of the decimal place.
Whole Number	A 64-bit (eight-byte) integer value.

The above table reference has been taken from Microsoft. Click here

Detection of Data Type in Power BI

Power query detects automatically detects the data type in a data set by inspecting the values.

If in any case Power Query fails to detect a data type or detects a wrong data type, then we can manually change or select it.

You can just click on the Icon appearing on the left side of the field name where a list will get open, from there you can select the data type. As shows in the image below.