Joining tables with Union and different columns

[Anonymous]

I want to use DAX to UNION 3 tables together. My issue is that 2 of the tables contains split columns...

Table1

ColumnA ColumnB ColumnC

Table2

ColumnA ColumnB

Table3

ColumnC

So normally, I could use 

UNION(
  SELECTCOLUMNS(Table1, "Title", ColumnA, "Name", ColumnB),
  SELECTCOLUMNS(Table2, "Title", ColumnA, "Name", ColumnB)
     )

But how can I incorporate ColumnC from Table1 and from Table3?

I'd like to use DAX and not have to merge via Power Query. 

[tamerj1]

Hi @Anonymous 

please try

=
UNION (
UNION (
SELECTCOLUMNS (
Table1,
"Title", Table1[ColumnA],
"Name", Table1[ColumnB],
"Value", Table1[Columnc]
),
SELECTCOLUMNS (
Table2,
"Title", Table2[ColumnA],
"Name", Table2[ColumnB],
"Value", BLANK ()
)
),
SELECTCOLUMNS (
Table3,
"Title", BLANK (),
"Name", BLANK (),
"Value", Table3[Columnc]
)
)

[Anonymous]

for some reason, this produced blank rows for Table3[ColumnC] values that match to Table2[ColumnA] and Table2[ColumnB] - the values for  Table3[ColumnC] did not pull in at all. 

[tamerj1]

@Anonymous 

Yes it happens sometimes. First adjust the code as follows (make sure the order of the columns in the code is correct)

=
UNION (
SELECTCOLUMNS (
Table1,
"Title", Table1[ColumnA],
"Name", Table1[ColumnB],
"Value", Table1[Columnc]
),
SELECTCOLUMNS (
Table2,
"Title", Table2[ColumnA],
"Name", Table2[ColumnB],
"Value", BLANK ()
),
SELECTCOLUMNS (
Table3,
"Title", BLANK (),
"Name", BLANK (),
"Value", Table3[Columnc]
)
)

If this didn't work, copy the code and create a new table then delete the old one.