Deleting in chunks with MySQL

问题

I'm trying to delete a large amount of data from my AWS RDS MySQL instance in chunks. I'm trying to adapt the code found in this link, but I'm stuck with a syntax error I cannot fix.

Error:

SQL Error (1064): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'main1: LOOP
    SELECT @z := operation_id FROM operations_test WHERE operation_id' at line 2

Code:

SET @apt = 'DTW'; 

SET @a = (SELECT MIN(operation_id) FROM operations_test);

BEGIN
    main1: LOOP
        SELECT @z := operation_id FROM operations_test WHERE operation_id >= @a ORDER BY operation_id LIMIT 1000,1;
        IF @z IS NULL THEN
          LEAVE main1;  -- last chunk
       END IF;
       DELETE operations_test, profiles_test FROM profiles_test LEFT JOIN operations_test ON operations_test.operation_id=profiles_test.operation_id WHERE operations_test.airport_id = @apt
            AND operations_test.operation_id >= @a
             AND operations_test.operation_id <  @z;
       DELETE operations_test FROM operations_test WHERE airport_id = @apt
            AND operation_id >= @a
             AND operation_id <  @z;
       SET @a = @z;
        SLEEP 1;  -- be a nice guy, especially in replication
    END LOOP main1;
END;
# Last chunk:
DELETE operations_test, profiles_test FROM profiles_test LEFT JOIN operations_test ON operations_test.operation_id=profiles_test.operation_id WHERE operations_test.airport_id = @apt
    AND id >= @a;
DELETE operations_test FROM operations_test WHERE airport_id = @apt
    AND id >= @a;

回答1:

The BEGIN ... END and LOOP statements are only valid in the context of a MySQL stored program (e.g. a PROCEDURE, FUNCTION, TRIGGER, )

As an example of usage:

DELIMITER $$

CREATE PROCEDURE foo 
BEGIN 
   SET ... ;
   SET ... ; 
   myloop: LOOP 
     ...
   END LOOP myloop;
END$$

DELIMITER ;

Given that we don't see a CREATE PROCEDURE statement, we're going to guess that the error message is the result of executing this as a bare statement. A syntax error is the expected result.

https://dev.mysql.com/doc/refman/5.7/en/begin-end.html

https://dev.mysql.com/doc/refman/5.7/en/loop.html

来源：https://stackoverflow.com/questions/50708512/deleting-in-chunks-with-mysql

标签

mysql

sql-delete