Remove last comma from dynamic sql

Question

How can I remove the last comma from part of a dynamic query

set @Query += '[A].[ID].&[' + Convert(varchar,SUBSTRING(@string, @start, @end - @start) ) +']&[CAN],[A].[ID].&[' +Convert(varchar,SUBSTRING(@string, @start, @end - @start) ) + ']&[usa],';

Answer 1

One general method uses functions LeftandLen

set @Query = Left(@Query,len(@Query)-1)

Update: Run the above statement after the while loop / Cursor contest or after cropping the entire request

Answer 2

Rephrase your logic and delete the first with stuff():

set @Query = ',[A].[ID].&[' + . . . ';

Then delete it as:

set @Query = stuff(@Query, 1, 1, '');