While represents repeated execution of an SQL statement or statement block.
- as long as the specified condition is true the statements are executed repeatedly
- the execution of statements in the WHILE loop can be controlled from inside the loop with the BREAK and CONTINUE keywords
Syntax:
WHILE Boolean_expression { statement_block | BREAK | CONTINUE }
Example
declare @t nvarchar(max)
declare @t1 nvarchar(max)declare @p int
set @t = 'fld1:"val1";fld2:"val2","val3";fld3:"val4";'
set @p = CHARINDEX(';', @t);while @p > 0
begin
set @t1 = SUBSTRING (@t, 0, @p)
set @t = SUBSTRING (@t, @p+1, len(@t) - @p)
set @p = CHARINDEX(';', @t);
select @t1
if @p = 0
break
else
continue
end
Result:
