LOOP Statements
- Loops repeat a statement or sequence of statements multiple times.
- There are three loop types:
- Basic loop
- FOR loop
- WHILE loop
Basic Loops
- Syntax :
LOOP
statement1;
. . .
EXIT [WHEN condition];
END LOOP;
- Example :
create or replace function f2() returns void as
$$
DECLARE
ctr numeric:=0;
BEGIN
LOOP
raise notice '%',ctr;
ctr:=ctr+1;
EXIT WHEN ctr > 3;
END LOOP;
END;
$$ language plpgsql;
WHILE Loops
- Syntax :
WHILE condition LOOP
statement1;
statement2;
. . .
END LOOP;
- Use the WHILE loop to repeat statements
- while a condition is TRUE.
- Use a FOR loop to shortcut the test for the numeric of iterations.
- Do not declare the counter; it is declared implicitly.
- 'lower_bound .. upper_bound' is required syntax.
FOR counter IN [REVERSE]
lower_bound..upper_bound LOOP
statement1;
statement2;
. . .
END LOOP;
- Example :
create or replace function f3() returns void as
$$
BEGIN
FOR ctr IN 1..3 LOOP
raise notice '%',ctr;
END LOOP;
END;
$$ language plpgsql;
Loop through Query Results
FOR record_or_row IN query LOOP
statements
END LOOP [ label ];
create or replace function f4() returns void as
$$
DECLARE
rec emp%ROWTYPE;
BEGIN
FOR rec IN select * from emp LOOP
raise notice '%',rec.ename;
END LOOP;
END;
$$ language plpgsql;
