Exists

The exists predicate specifies a result set of values to match in a where clause.

Syntax

     
    select * from ...
    where exists (select valX from ... where ...)
     
     

The not operator can be added to an expression using in:

 
    select * from ... 
    where not exists (select valX from ... where ...)
     

Examples

 
    create table dep(id int, name char(20));
    create table emp(name char(20), deptId int);
    insert into dep values([1,2,3],['Sales','Customer Service','Technical Support']);
    insert into emp values(['Smith','Jones','Black','Clark','Adams'], [3,3,1,2,1]);
     
    select name from emp where exists (select * from dep where id = emp.deptId and dep.id = 1);
    name
    ------------------------------------------------------------------------------
    Black
    Adams
 
    Selected records: 2
     

For more examples please see xSQL SDK sample exists.