Power Query: List.Max doesn't work on Date

[ovetteabejuela]

Hi,

Need some help. Supposedly List.Max should work on Dates right? Like List.Max([Date Column]).

I have a column of Date type and I tried to Add Column with the formula List.Max([Date Column]) but it's giving me this error:

Expression.Error: We cannot convert the value #date(2017, 10, 31) to type List.
Details:
Value=10/31/2017
Type=Type

So I might be missing something here...

[EILOOP]

This has been answered but the steps are not fully clear, for the New Power BI User I will break down the solution:

There currently is NO data type of "List", just make sure you have the column as Data or Number.

Here is where the confusing part comes in as the actual "List.Max()" function isnt complete in syntax you either have to know exactly how to code it or you need to make an adjustment in Advanced Editor Section to manualy type in the previous Query Step Name as "Table" reference.

I create a new Column I type the following in the column formual page "=List.Max({INSERT COLUMN NAME})" Add Column 

THEN I go into Advanced Editor and Copy the Query Name from the prior step in the front of my INSERTED COLUMN NAME.

BEFORE:   

#"Changed column type" = Table.TransformColumnTypes(Navigation, {{"ci_item_time", type date}}),  #"Added custom" = Table.AddColumn(#"Changed column type", "Custom", each List.Max([ci_item_time]))

AFTER:   

#"Changed column type" = Table.TransformColumnTypes(Navigation, {{"ci_item_time", type date}}),

#"Added custom" = Table.AddColumn(#"Changed column type", "Custom", each List.Max(#"Changed column type"[ci_item_time]))

NOW if you knew what your prior Query Step name was you could have manually coded this into the New Column Formula statement like List.Max(#"Changed column type"[ci_item_time]) I hope this clears up any confusion on this Topic.

E I L O O P

[jeffshieldsdev]

Old thread, but this is/was available on the Ribbon also: Transform tab > Date & Time Column section > Date > Latest 

It generates the same M as in this thread:

= List.Max(Source[Date])

[KasparsT]

Thanks for answer! Probably my question was not fully described... What I want to get is MAX DATE for particular customer number and have it sorted from list.

Example:

customer	date
1	18.06.2019
1	19.06.2019
1	20.06.2019
2	18.06.2019
2	19.06.2019
3	20.06.2019

Thanks!

[Anonymous]

Whats the context of the power query line of code?  Are you passing a column or list type to the function?  The error message reads like you have passed a since value of type Date.

[ovetteabejuela]

So I added a column with this formula:

=List.Max([Date Column])

[v-huizhn-msft · Accepted solution]

Hi @ovetteabejuela,

As I tested, you need to create the date column as a list, then use it in List.Max(). I have the following sample table.

2. Create a custom column using the formula.

=List.Max(#"Changed Type"[Date])

3. You will get the expected result as follows.



Best Regards,
Angelia

[StephenF]

How do i do this with an Column of type Int? There is no such thing as a list item in the dropdown i can transform this too.

[KasparsT]

Hi @v-huizhn-msft!

But how to get max date for each Customer number if it have few of them?

Thanks 

Kaspars

[Anonymous]

So when you look at the actual code in the Advanced Editor, does this come after an 'each' statement?  If so, you are passing a single value into that statement.

[MarcelBeug]

The column name must be preceded by the table name, which can be either the name of another query or the name of another step in the current query.

=List.Max(Table[Date Column])

[parry2k]

your column type is List? That function is to find max in a list or use groupby function to get maximum date.