MySQL，复制被选定字段从一个表到另一个(MYSQL, Copy selected fields

在MySQL中，如何复制一个字段与所有记录TABLE1到TABLE2对应一个主键，即： EMPLOYEE no. ？

Answer 1:

试试这个

INSERT INTO `table2` (`field_name2`) SELECT `field_name` FROM `table1`

Answer 2:

如果你的意思是你想用另一个表的列更新一个表的列，那么这里有一些选择：

1. 一个连接：

    UPDATE table1 AS t1 INNER JOIN table2 AS t2 ON t1.EmpoyeeNo = t2.EmployeeNo SET t1.SomeColumn = t2.SomeColumn 

   或者它可能是一个左连接：

    UPDATE table1 AS t1 LEFT JOIN table2 AS t2 ON t1.EmpoyeeNo = t2.EmployeeNo SET t1.SomeColumn = t2.SomeColumn 

   这将基本上是空的（设置为NULL）不匹配发生时的值。

2. 子查询：

    UPDATE table1 SET SomeColumn = ( SELECT SomeColumn FROM table2 WHERE EmployeeNo = table1.EmployeeNo ) 

   这是在＃1等同于左连接解决方​​案。

请注意，在所有情况下，假设在一排table1可以匹配不超过一个排table2 。

Answer 3:

为将数据复制到另一个查询从一个表：

Insert into table2 (field1, field2)  select field1, field2 from table1

如果你只想复制选定的值，然后用在查询的WHERE子句

Insert into table2 (field1, field2)  select field1, field2 from table1 where field1=condition

Answer 4:

update
  table1 t1
  join table2 t2 on t2.field = t1.field
set
  t1.field1 = t2.matchingfield
where
  t1.whatever = t2.whatever

Answer 5:

你可以用这个来的所有记录从复制table1至table2与条件。

Insert into table2  select  * from table1 where field1=condition

Answer 6:

INSERT INTO table_1 （ column-1 ， column-2 ）SELECT柱1，柱2 FROM TABLE_2;

Answer 7:

Insert into Delivery (DeliveredDate, appid, DownloadSize, UploadSize) select Delivered, Appid, DownloadSize,UploadSize from Delivery_Summary;

文章来源: MYSQL, Copy selected fields from one table to another