MYSQL更新语句内部联接表

一尘不染

MYSQL更新语句内部联接表

mysql

我不知道是什么问题。使用MySQL 5.0尝试运行以下MYSQL更新语句时出现编译错误

  UPDATE  b
SET b.mapx = g.latitude,
  b.mapy = g.longitude
FROM business AS b
INNER JOIN business_geocode g ON b.business_id = g.business_id
WHERE  (b.mapx = '' or b.mapx = 0) and
  g.latitude > 0

所有字段名称都是正确的。有什么想法吗？

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2020-05-17

共1个答案

一尘不染

尝试这个：

UPDATE business AS b
INNER JOIN business_geocode AS g ON b.business_id = g.business_id
SET b.mapx = g.latitude,
  b.mapy = g.longitude
WHERE  (b.mapx = '' or b.mapx = 0) and
  g.latitude > 0

更新：

既然您说查询产生了语法错误，所以我创建了一些可以对其进行测试的表，并确认查询中没有语法错误：

mysql> create table business (business_id int unsigned primary key auto_increment, mapx varchar(255), mapy varchar(255)) engine=innodb;
Query OK, 0 rows affected (0.01 sec)

mysql> create table business_geocode (business_geocode_id int unsigned primary key auto_increment, business_id int unsigned not null, latitude varchar(255) not null, longitude varchar(255) not null, foreign key (business_id) references business(business_id)) engine=innodb;
Query OK, 0 rows affected (0.01 sec)

mysql> UPDATE business AS b
    -> INNER JOIN business_geocode AS g ON b.business_id = g.business_id
    -> SET b.mapx = g.latitude,
    ->   b.mapy = g.longitude
    -> WHERE  (b.mapx = '' or b.mapx = 0) and
    ->   g.latitude > 0;
Query OK, 0 rows affected (0.00 sec)
Rows matched: 0  Changed: 0  Warnings: 0

看到？没有语法错误。我针对MySQL 5.5.8进行了测试。

2020-05-17