Looking for correct SQL for Previous Month of Column to create a new column

[JulieL4108]

PREVIOUSMONTH('Query1[Date_field]) not working [Date_field] references a column in the table, but no returns of prior month of the date?

[JulieL4108]

Apologies I am new and may not have asked the question properly.  I have a date column and want to create a new date column 1 month prior than the original date column.  

[v-xinruzhu-msft · Accepted solution]

Hi @JulieL4108 

If you want to add a calculated column by dax,You can use edate() function. 

e.g 

Column =
EDATE ( 'Query1'[Date_field], -1 )

Output

If you want to implement it in power query, you can add a custom column and input the following code

Date.AddMonths([Date_field],-1)

Output

Best Regards!

Yolo Zhu

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

[JulieL4108]

Thank you!  I kept adding in 'm' in the front of the field EDATE('m','Query1'[date_field],-1) thinking I needed to indicate month and kept receiving an error.

[lbendlin]

EDATE (<column> , -1 )