I thought this was a neat solution I came up with, but I'm sure it's
been thought of before. Anyway, it's my first post here.
We have a process for importing data which generates a SELECT statement
based on user's stored configuration. Since the resulting SELECT statement
can be massive, it's created and stored in a text field in a temp table.
So how do I run this huge query after creating it? In my tests, I was
getting a datalength > 20000, requiring 3 varchar(8000) variables in
order to use the execute command. Thing is, I don't know how big it could
possibly get, I wanted to be able to execute it regardless.
Here's what I came up with, it's very simple:
Table is named #IMPORTQUERY, one field SQLTEXT of type TEXT.
declare @x int, @s varchar(8000)
select @x = datalength(sqltext) / 8000 + 1, @s = 'execute('''')' from #importquery
while @x > 0
select @s = 'declare @s' + cast(@x as varchar) + ' varchar(8000) ' +
'select @s' + cast(@x as varchar) +
'=substring(sqltext,@x,@x+8000),@x=@x+8000 from #importquery ' +
replace(@s,'execute(','execute(@s' + cast(@x as varchar) + '+')
, @x = @x - 1
set @s = 'declare @x int set @x=1 ' + @s
At the end, I execute the "@s" variable which is SQL that builds and
executes the massive query. Here's what @s looks like at the end:
declare @x int set @x=1
declare @s1 varchar(8000)
select @s1=substring(sqltext,@x,@x+8000),@x=@x+8000 from #importquery
declare @s2 varchar(8000)
select @s2=substring(sqltext,@x,@x+8000),@x=@x+8000 from #importquery
declare @s3 varchar(8000)
select @s3=substring(sqltext,@x,@x+8000),@x=@x+8000 from #importquery