How to write a sql2000 query statement may have loops or cursors

Loops or cursors can only be used in stored procedures, and it is recommended to use stored procedures to solve complex situations like yours.

select , zsl, ,1 sxfrom stk t1, stkdtl t2where =

and = 1

union all

select , zsl, ,1 sxfrom stk t1, stkdtl t2where =

and = 2

union all

select , zsl, ,2 sxfrom stk t1, stkdtl t2where =

and = 2

union all

select , zsl, ,1 sxfrom stk t1, stkdtl t2where =

and = 3

union all

select , zsl, ,2 sxfrom stk t1, stkdtl t2where =

and = 3

union all

select , zsl, ,3 sxfrom stk t1, stkdtl t2where =

and = 3

Although it is troublesome, you can only rely on SQL query statements to achieve the loop...

The SQL cursor can also be seen as a kind of loop, and the select number from student has more than one record queried here, so it will continue to loop.

To define cursor handling, the following is to find out the utterances that match the criteria.

select *

from table

where column name like'w%'

and Listed Names ='w6001'

and Listed Names ='w6300'

close tnames_cursor

To release after closing, that is, to delete.

deallocate tnames cursor -- release the cursor.

select top1 customerid from indicates that only one row is taken. The meaning here is to take the customerID column of a row.

distinct customerid means to filter out duplicate data. Only unique rows are displayed.

1. Fetch the customerID of the first piece of data in the subquery result.

2. No, you cannot. top 1 is the first entry of the query result, and distinct is to remove the duplicates of the query result, and the two have different meanings.

SQL (Standard Structured Query Language) does not include program flow control statements, while Microsoft's T-SQL (Enhanced Structured Query Language) has circular statements (while).

For example: declare @num int -- declare the @num memory variable of the integer.

select @num=0 --the value of the integer variable is 0while @num<10 @num the value of the integer variable is 0 --set, and when the @num is greater than or equal to 10, the loop will be ended.

begin -- the beginning of the cycle.

select @num=@num+1 --Add 1select @num to the @num --Show @num value end --End of the loop body.

The program execution displays a number of 1-10.

SQL doesn't have loops, you have to use processes to implement them, for example.

beginfor i in 1 ..9 loop

dbms_;

end loop;

end;/

No. Looping statements are implemented by a native program such as PHP.

You can write a function in a stored procedure or call it in an SQL statement.