MID Returns a string of characters from the middle of a text string, given a starting position and length.
Syntax
MID(text, start_num, num_chars)
Parameters
text – The text string from which you want to extract the characters, or a column that contains text.
start_num – The position of the first character you want to extract. Positions start at 1.
num_chars – The number of characters to return.
Return Value
A string of text of the specified length.
Reference Data
https://docs.microsoft.com/en-us/dax/dax-function-reference