Query: Add column at the beginning

[Gangula]

When we use the add column function in power query, it adds the new column at the very last. Is there a way to create it at the very beginning?

I don't want to move it to the beginning using the right click option because my column headers might change.

[zoloturu · Accepted solution]

@Gangula,

To do that you would need to add two additional steps between your data table and reordering like below:

let    
   ...
    TableData = Table.AddColumn(TransformColumnTypes, "Half Year", each if [Month] < 7 then 1 else 2),
    ColumnNames = Table.ColumnNames(TableData),
    ReorderedList = List.Combine({{"Half Year"},List.FirstN(ColumnNames,List.Count(ColumnNames)-1)}),
    Result = Table.ReorderColumns(TableData,ReorderedList)
in
 Result

where

- TableData is the last step of your data, in my case, it is a step where I've added a new custom column

- Half Year is my custom column which I want to be first each time

- ColumnNames is a step which contains a list of columns from TableData

- ReorderedList is a step which represents column names where my custom column comes first and all other column next (does not matter how many)

- Result is a step represents sorted TableData based on ReorderedList 

Regards,
Ruslan
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[Anonymous]

Perfect solution to my problem! I keep forgetting that GUI generates steps with static information, which can be replaced with more dyamic code. My issue was insertion of two columns after unknow number of "garbage" columns. Well, they are not really garbage, but they have dates across in the first line and values under each date (pivot). So I had to move 2 newly added columns to the front before promoting headers and unpivoting the dates. Your solutions works perfectly! Thanks.

[Gangula]

Thank you Ruslan, that was awesome.
Related to the same issue, is there a way to order columns when a column is not at the end.

For example, I want to first move a column to end and then use the process above to sort the columns. Is this possible?

[zoloturu]

@Gangula,

It is achievable as well, just need to replace List.FirsN with List.RemoveMatchingItems:

let
    ...
    TableData = Table.AddColumn(TransformColumnTypes, "Half Year", each if [Month] < 7 then 1 else 2),
    ColumnNames = Table.ColumnNames(TableData),
    ReorderedList = List.Combine({{"Half Year"},List.RemoveMatchingItems(ColumnNames,{"Half Year"})}),
    Result = Table.ReorderColumns(TableData,ReorderedList)
in
    Result

Regards,
Ruslan
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[Gangula]

Awesome, Thanks a lot

[Greg_Deckler]

Add your column. Demote your headers. Reorder. Promote your headers.

[Gangula]

I haven't tried this yet, but wouldn't it be a problem if the total number of columns in my source increase?

[Greg_Deckler]

Yep, could be. Maybe @ImkeF has a different suggestion.