MYSQL, Copy selected fields from one table to another

Question

In MySQL, How do I copy a FIELD with all RECORDS from TABLE1 to TABLE2 which corresponds to a primary key ie: EMPLOYEE no.?

Answer 1

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

Answer 2

Suppose if the table structure is as follows.

TableA - Col1, Col2 ,Col3 TableB - Col1, Col2 ,Col3

There is no need to select all column of the table to transfer data from 1 table to another table in same databse. You can copy (insert) the rows from TableA to TableB.

Code as follows -

Insert into TableB (Col1, Col2 ,Col3)
Select Col1, Col2 ,Col3 from TableA

You can also do this -

Insert into TableB (Col1, Col2, Col3) 
Select * from TableA

Both codes work , you need to see your requirement.

Generic code -

INSERT INTO table2 (column1, column2, column3, ...)
SELECT column1, column2, column3, ...
FROM table1
WHERE condition;

You can add 'Where' condition if you need.

Thank you!!!

Answer 3

Try this

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

Answer 4

You can use this to copy all the records from table1 into table2 with a condition.

Insert into table2  select  * from table1 where field1=condition

Answer 5

If you mean you want to update one table's column using another table's column, then here are some options:

1. A join:

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

   Alternatively it could be a left join:

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

   which would essentially empty (set to NULL) the values where no match occurred.

2. A subquery:

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

   This is equivalent to the left join solution in #1.

Note that in all cases it is assumed that a row in table1 can match no more than one row in table2.

Answer 6

INSERT INTO table_1(column-1, column-2) SELECT column-1, column-2 FROM table_2;