smu4NgMp

1if ((select *
2     from table1 
3     where quant>1000) is not null) 
4then ... 
5else RAISE error$e; 
6end if;
7	
8if exists (select *
9         from table1 
10         where quant>1000)
11	
12create table table1 (quant number);
13insert into table1 values (0); 
14
15declare
16    function existsHighQuant return boolean is
17    begin
18        for r in (select 1 from table1 where quant>1000) loop return true; end loop; return false;
19    end;
20    -- или так - не очень изящный по моему мнению вариант 
21    function existsRow(stmt varchar2) return boolean is
22       curs sys_refcursor;
23       dummy number;
24    begin 
25        open curs for stmt; fetch curs into dummy; return curs%found;
26    end;
27begin 
28    if existsHighQuant then 
29        null; --do something
30    else 
31        raise_application_error(-20000, 'quant gt 1000 not found'); 
32    end if;
33
34    if existsRow('select 1 from table1') then dbms_output.put_line('at least 1 row exists'); end if;
35end;
36/
37
38ORA-20000: quant gt 1000 not found
39
40insert into table1 values (2000); 
41-- повторить вызов блока
42
43PL/SQL procedure successfully completed.
44at least 1 row exists