Question

表1：mydata_table
多列。但我想获取3列不同的记录。

Email_Office | Email_Personal1 | Email_Personal2

表2：unique_emails

只有3列。 Email_Office | Email_Personal1 | Email_Personal2

我为表2的所有三列尝试了此代码，以便从每列插入不同的记录。

insert into unique_emails 
(email_personal1) 
select distinct email_personal1
from mydata_table
where Email_Personal1!=""

它插入了记录，但问题是如果email_office列中有100行，email_personal1中有300行，那么它将显示前100行包含email_office，其余两列为空，然后从第101行开始，它将显示email_personal1的记录剩下的两列是空的。我想将所有行插入在一起。我怎么能这样做？

Answer 1

如果要插入唯一的电子邮件三元组，则应使用

insert into unique_emails 
(email_office, email_personal1, email_personal2) 
select distinct email_office, email_personal1, email_personal2
from mydata_table
where email_office!="" OR Email_Personal1!="" OR Email_Personal2!=""

但在这种情况下，某些电子邮件可能会在表unique_emails中多次出现。

假设表1包含记录：

Email_Office | Email_Personal1 | Email_Personal2
------------------------------------------------
a@a.com        b@b.com           c@c.com
a@a.com        b@b.com           c@c.com
a@a.com        b@b.com           e@e.com
a@a.com        c@c.com           NULL
a@a.com        d@d.com           e@e.com

然后结果表2

 Email_Office | Email_Personal1 | Email_Personal2   
------------------------------------------------
a@a.com        b@b.com           c@c.com
               c@c.com           e@e.com
               d@d.com

<强> UPD。试试这个：（SQL Fiddle）

insert into unique_emails 
(email_office, email_personal1, email_personal2)
select b.email_office, c.email_personal1, d.email_personal2
from (
  select @i := @i + 1 AS pos from mydata_table, (select @i := 0) r) a
left join (
  select t.*, @j := @j + 1 AS pos
  from (select distinct email_office from mydata_table where email_office!="") t,
    (select @j := 0) r) b on b.pos = a.pos
left join (
  select t.*, @k := @k + 1 AS pos
  from (select distinct email_personal1 from mydata_table where email_personal1!="") t,
    (select @k := 0) r) c on c.pos = a.pos
left join (
  select t.*, @l := @l + 1 AS pos
  from (select distinct email_personal2 from mydata_table where email_personal2!="") t,
    (select @l := 0) r) d on d.pos = a.pos
where b.email_office is not null or c.email_personal1 is not null or d.email_personal2 is not null

Answer 2

尝试为需要唯一的列创建唯一索引，并使用@Sergey提出的第一个使用ignore的SQL：

INSERT IGNORE INTO
  unique_emails 
  (email_office, email_personal1, email_personal2) 
  SELECT DISTINCT
    email_office,
    email_personal1,
    email_personal2
  FROM
    mydata_table
  WHERE
    email_office!=""
    OR Email_Personal1!=""
    OR Email_Personal2!=""

将一个表的不同记录插入到MySQL中

2 个答案: