SQL Tutorial - Cursors
1. Cursors
DELIMITER //
CREATE PROCEDURE cursorExample (
)
BEGIN
DECLARE done INTEGER DEFAULT 0;
DECLARE theName varchar(100) DEFAULT "";
-- declare cursor
DEClARE curName
CURSOR FOR
SELECT username FROM app_user;
-- declare NOT FOUND handler
DECLARE CONTINUE HANDLER
FOR NOT FOUND SET done = 1;
OPEN curName;
myLoop: LOOP
FETCH curName INTO theName;
IF finished = 1 THEN
LEAVE myLoop;
END IF;
-- provide output
select theName;
END LOOP myLoop;
-- Clean up when we are done
CLOSE curName;
END//
DELIMITER ;
DELIMITER //
CREATE OR REPLACE PROCEDURE cursorExample (
)
BEGIN
DECLARE done INTEGER DEFAULT 0;
DECLARE theName varchar(100) DEFAULT "";
DECLARE output varchar(1000) DEFAULT "";
-- declare cursor
DECLARE myCursor
CURSOR FOR
SELECT username FROM app_user;
-- declare NOT FOUND handler
DECLARE CONTINUE HANDLER
FOR NOT FOUND SET done = 1;
OPEN myCursor;
myLoop: LOOP
FETCH myCursor INTO theName;
IF done = 1 THEN
LEAVE myLoop;
END IF;
-- provide output
set theName = concat(theName,", ");
set output = concat(output,theName);
END LOOP myLoop;
-- Clean up when we are done
CLOSE myCursor;
select output;
END//
DELIMITER ;
DELIMITER //
CREATE OR REPLACE PROCEDURE cursorExample (
)
BEGIN
DECLARE done INTEGER DEFAULT 0;
DECLARE theName varchar(100) DEFAULT "";
DECLARE theLogin varchar(100) DEFAULT "";
DECLARE output varchar(1000) DEFAULT "";
-- declare cursor
DECLARE myCursor
CURSOR FOR
SELECT userName,userLogin FROM app_user;
-- declare NOT FOUND handler
DECLARE CONTINUE HANDLER
FOR NOT FOUND SET done = 1;
OPEN myCursor;
myLoop: LOOP
FETCH myCursor INTO theName,theLogin;
IF done = 1 THEN
LEAVE myLoop;
END IF;
-- provide output
set theLogin = concat(" [",theName,"]");
set theName = concat(theName,theLogin," | ");
set output = concat(output,theName);
END LOOP myLoop;
-- Clean up when we are done
CLOSE myCursor;
select output;
END//
DELIMITER ;
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