While Loop in Azure SQL -

in azure stream analytics query want write while loop using declare/set counting.

declare @x int set @x = 0 while @x < 90 begin set @x = @x + 1  *my code '@x' counter*  end 

the error message claims:

declare @x int unsupported statement.

is there basic overlooked?

if comment out declare command, asa sql doesn't set command.

if leave out while loop , replace @x number in code, works fine.