Question

我需要编写单个查询，如果该值已经存在于同一表中，它将更新行并跳过行。即，仅当该团队不在同一事件（eventID）的游戏中时，我才希望将其更新为游戏。

这是查询

update tbl_games m INNER JOIN bcs_event e on e.id = m.eventID SET m.team_id=1;

我尝试在where语句中遵循以下两种解决方案

WHERE(NOT EXISTS(select m1.id from tbl_games  as m1 where m1.eventID=e.id and m1.team_id=1 ))

这句话是“您不能在FROM子句中指定目标表'm'进行更新”

WHERE (NOT EXISTS(select * from (select m1.id from tbl_games as m1 where m1.eventID=e.id and m1.team_id=1) as tmp))

这是说“'where子句'中的未知列'e.id'”

以下是示例数据

CREATE TABLE bcs_event (
  `id` INT NOT NULL AUTO_INCREMENT,
  `Name` VARCHAR(45) NULL,
  PRIMARY KEY (`id`));

CREATE TABLE tbl_games (
  `id` INT NOT NULL AUTO_INCREMENT,
  `event_id` INT NULL,
  `team_id` INT NULL,
  PRIMARY KEY (`id`),
  INDEX `evid_idx` (`event_id` ASC),
  CONSTRAINT `evid`
    FOREIGN KEY (`event_id`)
    REFERENCES bcs_event (`id`)
    ON DELETE NO ACTION
    ON UPDATE NO ACTION);

INSERT INTO bcs_event (`Name`) VALUES ('Softball Event');
INSERT INTO bcs_event (`Name`) VALUES ('Baseball Event');
INSERT INTO bcs_event (`Name`) VALUES ('Soccer Event');

INSERT INTO tbl_games (`event_id`, `team_id`) VALUES ('1', '11');
INSERT INTO tbl_games (`event_id`, `team_id`) VALUES ('1', '22');
INSERT INTO tbl_games (`event_id`) VALUES ('1');
INSERT INTO tbl_games (`event_id`) VALUES ('1'); 

update tbl_games m INNER JOIN bcs_event e on e.id = m.event_id SET m.team_id=11
where m.team_id is NULL and (NOT EXISTS(select g.id from tbl_games as g where g.eventID=e.id and g.team_id=11));

Answer 1

尝试一下：

CREATE TABLE bcs_event (
  `id` INT NOT NULL AUTO_INCREMENT,
  `Name` VARCHAR(45) NULL,
  PRIMARY KEY (`id`));

✓

CREATE TABLE tbl_games (
  `id` INT NOT NULL AUTO_INCREMENT,
  `event_id` INT NULL,
  `team_id` INT NULL,
  PRIMARY KEY (`id`),
  INDEX `evid_idx` (`event_id` ASC),
  CONSTRAINT `evid`
    FOREIGN KEY (`event_id`)
    REFERENCES bcs_event (`id`)
    ON DELETE NO ACTION
    ON UPDATE NO ACTION);

✓

INSERT INTO bcs_event (`Name`) VALUES ('Softball Event');
INSERT INTO bcs_event (`Name`) VALUES ('Baseball Event');
INSERT INTO bcs_event (`Name`) VALUES ('Soccer Event');
INSERT INTO tbl_games (`event_id`, `team_id`) VALUES ('1', '11');
INSERT INTO tbl_games (`event_id`, `team_id`) VALUES ('1', '22');
INSERT INTO tbl_games (`event_id`) VALUES ('1');
INSERT INTO tbl_games (`event_id`) VALUES ('1');

✓

update tbl_games m 
INNER JOIN bcs_event e 
  on e.id = m.event_id 
SET m.team_id=11
where m.team_id is NULL and 
NOT EXISTS ( 
  select l.id 
  from (select g.id from tbl_games as g 
  where g.event_id=(SELECT e.id 
                         FROM   bcs_event e 
                         WHERE e.id = g.event_id) and g.team_id=11) l
  );

✓

db <>提琴here

MySQL-如果同一表的其他行中不存在值，则更新行

1 个答案: