SQL ELIMINAR con UNIRSE a otra tabla para la condición WHERE

Tengo que eliminar filas de guide_category que no tienen relación con la tabla guide (relaciones muertas).

Esto es lo que quiero hacer, pero por supuesto no funciona.

DELETE FROM guide_category AS pgc 
 WHERE pgc.id_guide_category IN (SELECT id_guide_category 
                                   FROM guide_category AS gc
                              LEFT JOIN guide AS g ON g.id_guide = gc.id_guide
                                  WHERE g.title IS NULL)

Error:

No se puede especificar la tabla de destino 'guide_category' para la actualización en la cláusula FROM

Author: Sam, 2009-12-30
Source

4 answers

Debido a los problemas de implementación de bloqueo, MySQL no permite hacer referencia a la tabla afectada con DELETE o UPDATE.

Necesitas hacer un JOIN aquí en su lugar:

DELETE  gc.*
FROM    guide_category AS gc 
LEFT JOIN
        guide AS g 
ON      g.id_guide = gc.id_guide
WHERE   g.title IS NULL

O simplemente use un NOT IN: 

DELETE  
FROM    guide_category AS gc 
WHERE   id_guide NOT IN
        (
        SELECT  id_guide
        FROM    guide
        )
 104
Author: Quassnoi,
Warning: date(): Invalid date.timezone value 'Europe/Kyiv', we selected the timezone 'UTC' for now. in /var/www/agent_stack/data/www/ajaxhispano.com/template/agent.layouts/content.php on line 61
2009-12-30 15:31:09

Creo que, por su descripción, lo siguiente sería suficiente: 

DELETE FROM guide_category 
WHERE id_guide NOT IN (SELECT id_guide FROM guide)

Asumo, que no hay restricciones de integridad referencial en las tablas involucradas, ¿existen?

 9
Author: Dirk,
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2009-12-30 15:35:19

Pruebe este ejemplo de scripts SQL para facilitar la comprensión,

CREATE TABLE TABLE1 (REFNO VARCHAR(10))
CREATE TABLE TABLE2 (REFNO VARCHAR(10))

--TRUNCATE TABLE TABLE1
--TRUNCATE TABLE TABLE2

INSERT INTO TABLE1 SELECT 'TEST_NAME'
INSERT INTO TABLE1 SELECT 'KUMAR'
INSERT INTO TABLE1 SELECT 'SIVA'
INSERT INTO TABLE1 SELECT 'SUSHANT'

INSERT INTO TABLE2 SELECT 'KUMAR'
INSERT INTO TABLE2 SELECT 'SIVA'
INSERT INTO TABLE2 SELECT 'SUSHANT'

SELECT * FROM TABLE1
SELECT * FROM TABLE2

DELETE T1 FROM TABLE1 T1 JOIN TABLE2 T2 ON T1.REFNO = T2.REFNO

Su caso es: 

   DELETE pgc
     FROM guide_category pgc 
LEFT JOIN guide g
       ON g.id_guide = gc.id_guide 
    WHERE g.id_guide IS NULL
 4
Author: user2384628,
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2013-05-15 07:11:47

Qué tal: 

DELETE guide_category  
  WHERE id_guide_category IN ( 

        SELECT id_guide_category 
          FROM guide_category AS gc
     LEFT JOIN guide AS g 
            ON g.id_guide = gc.id_guide
         WHERE g.title IS NULL

  )
 -2
Author: Philippe Leybaert,
Warning: date(): Invalid date.timezone value 'Europe/Kyiv', we selected the timezone 'UTC' for now. in /var/www/agent_stack/data/www/ajaxhispano.com/template/agent.layouts/content.php on line 61
2009-12-30 15:30:47