MaxString / MinString question

[flo2]

Hello,

I ued the MaxString function to group duplicates. ( same id of person but for one text field, one has blank value and the other one no so I want to take the not empty value )

And so I checked the use of this function, it uses the ANSI character and i suppose it does the sum of the AINSI value. 

So if we have an field with empty values and an ' OK ' value it will take the OK one ( cause sum of ANSI value is superior )

But i have a problem when there is a date when i make some tests. for example

If I have these values, so 4 empty lines and one which has one date, if I use group by and for the second column I use MaxString, according to me it should return the date, but it doesn't, it returns a blank value. 

( code is

table1:
LOAD A,
B
FROM
[testMaxString.xlsx]
(ooxml, no labels);

table2:
NoConcatenate
load
A,
MaxString(B) as B
resident table1
group by A;
drop table table1;

So i have understood that i sould use the Max Function for numeric values, but still, why MaxString doesn't return the date, the sum of ansi character are superior to blank values no ? 

thanks !

[rwunderlich]

According to the doc, MaxString returns the last value in sort order.  Blank will sort after numbers, so I think you can swap in a null for blanks to get what you want. 

MaxString(if(len(Trim(B)) = 0, null(), B)) as B 

-Rob
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