Question

我在为三个表中的uninon指定select语句中的条件时遇到问题。这是我的代码

create table master_data(
select id,number,product_id
from tablename_A
where id REGEXP '^[0-9]*$' and id != ' ' and product_id != 0 and product_id is not null
union
select id,number,product_id
from tablename_B
where id REGEXP '^[0-9]*$' and id != ' ' and product_id != 0 and product_id is not null
union
select id,number,product_id
from tablename_C
where id REGEXP '^[0-9]*$' and id != ' ' and product_id != 0 and product_id is not null
);

我收到此错误：

您的SQL语法有错误;检查手册对应于您的MySQL服务器版本，以便使用正确的语法 'id！=''和product_id！= 0附近，而product_id不是 nullunionselect id'在第8行

Answer 1

首先，什么是＆＃39; REGEXP＆＃39; ？

我更喜欢这个：

WITH master_data AS 
(
   select
      id,
      number,
      product_id 
   from
      tablename_A 
   union
   select
      id,
      number,
      product_id 
   from
      tablename_B 
   union
   select
      id,
      number,
      product_id 
   from
      tablename_C 
)
SELECT
   * 
FROM
   master_data 
WHERE
   id NOT IN '^[0-9]*$' 
   and id != ' ' 
   and product_id != 0 
   and product_id is not null

Answer 2

以下在mysql 5.6.31（Microsoft Server）和mysql 5.7.14（Redhat Linux）上运行良好

create table tablename_A
(   id int not null,
    product_id int not null,
    number int not null
);
create table tablename_B
(   id int not null,
    product_id int not null,
    number int not null
);
create table tablename_C
(   id int not null,
    product_id int not null,
    number int not null
);


create table master_data as
select id,number,product_id
from tablename_A
where (id REGEXP '^[0-9]*$') and id != ' ' and product_id != 0 and product_id is not null
union
select id,number,product_id
from tablename_B
where (id REGEXP '^[0-9]*$') and id != ' ' and product_id != 0 and product_id is not null
union
select id,number,product_id
from tablename_C
where id REGEXP '^[0-9]*$' and id != ' ' and product_id != 0 and product_id is not null;

在Mysql中使用Union in Select语句

2 个答案: