if statement in a new column not working

[benjamin_sasin]

New to Power Query M here, I'm converting a source column's YYYYMM  to date, which works well, except it produces an error whenever the source column is null.

I'm trying to wrap an IF statement in that to cope with the error (BTW can't find any reference to IF statements in the documentation?)

Table.AddColumn(#"Changed Type", "GRADYEARMONTH", each   Date.FromText(Text.Combine({Text.Start([GRADYYYYMM],4),Text.End([GRADYYYYMM],2),"01"},"-")))

Becomes:

Table.AddColumn(#"Changed Type", "GRADYEARMONTH", each if Text.Length([GRADYYYMM])<6 null else  Date.FromText(Text.Combine({Text.Start([GRADYYYYMM],4),Text.End([GRADYYYYMM],2),"01"},"-")))

But it won't take that. Surely I messed up something, but what?

[gpoggi · Accepted solution]

Hi @benjamin_sasin ,

Yep, it is only syntax problem, please try instead:

if
  [GRADYYYYMM] = null or Text.Length([GRADYYYYMM]) < 6
then
  null
else
  Date.FromText(Text.Combine({Text.Start([GRADYYYYMM],4),Text.End([GRADYYYYMM],2),"01"},"-"))

IF SYNTAX in M Language:

if <test> then <output1> else <output2> 

NESTED SYNTAX (just append the if after else and everything is the same):

if <test> then <output1> else if <test2> then <output2> else if <test3> then <output3> else <output4>

Any question, just let me know,

Regards,

Gian Carlo Poggi

[benjamin_sasin]

I forgot the "then"--duh (facepalm)! Thanks a lot!