sql - teradata row_number() over(partition by X , Y order by Z desc) = 1 -
i use in teradata sql assistant:
row_number() over(partition x||y order z desc) = 1
my colleague uses same difference doesn't enter "||" between 2 attributes, enters ",". tested small data both , not find difference in output.
my assumption using "||" kind of concatenation of 2 attributes (x , y). true or not?
does difference between "||" , "," in command?
many in advance..
the 2 similar. however, version commas is correct (for purposes). consider happens in these cases:
x y bc ab c
the concatenation version combine them both "abc", don't want that. comma version treats values ('a', 'bc') , ('ab', 'c'), separate -- if did group x, y
.
only concatenate values if intention.
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