使用MySQL将数据从一列复制到另一张表中的另一列

Question

I am trying to copy data from one column to another column in a different table using MySQL but the table that I am importing into has a foreign key restraint that is preventing me from doing this;

Here is the table that I would like to import from (product_code) column

Table1

+----+--------------+-------------+-------+--------------+-----------+---------+-------+-------+
| id | product_code | distributor | brand | productname  | wheelsize | pcd_1   | pcd_2 | pcd_3 |
+----+--------------+-------------+-------+--------------+-----------+---------+-------+-------+
|  1 | F7050MHS20A2 | *******     | MAK   | MOHAVE       | 7 x 15    | 5x139.7 |       |       |
|  2 | 3480         | *******     | KFZ   | Winter Steel | 4.5 x 13  | 3x98    |       |       |
|  3 | 3480         | *******     | KFZ   | Winter Steel | 4.5 x 13  | 3x98    |       |       |
|  4 | 3480         | *******     | KFZ   | Winter Steel | 4.5 x 13  | 3x98    |       |       |
|  5 | 3480         | *******     | KFZ   | Winter Steel | 4.5 x 13  | 3x98    |       |       |
|  6 | 3480         | *******     | KFZ   | Winter Steel | 4.5 x 13  | 3x98    |       |       |
|  7 | 3480         | *******     | KFZ   | Winter Steel | 4.5 x 13  | 3x98    |       |       |
|  8 | 3480         | *******     | KFZ   | Winter Steel | 4.5 x 13  | 3x98    |       |       |
|  9 | 3480         | *******     | KFZ   | Winter Steel | 4.5 x 13  | 3x98    |       |       |
| 10 | 3480         | *******     | KFZ   | Winter Steel | 4.5 x 13  | 3x98    |       |       |
+----+--------------+-------------+-------+--------------+-----------+---------+-------+-------+

I would like to copy the product_code column into the sku column

Table2

+----------+----------+-------+--------------+
| id       | value_id | pid   | sku          |
+----------+----------+-------+--------------+
| 20315857 |   369781 | 41257 | 001          |
| 20315858 |   369782 | 41256 | Config - ST5 |
+----------+----------+-------+--------------+

The problem is that the value_id column in Table2 is referencing value_id Table3 so I either get a Foreign key restraint error or lock wait timeout

 a foreign key constraint fails (`gravytra_topgear`.`am_finder_map`, CONSTRAINT `FK_MAP_VALUE` FOREIGN KEY (`value_id`) REFERENCES `am_finder_value` (`value_id`) ON D

Table 3

+----------+-----------+-------------+----------------+
| value_id | parent_id | dropdown_id | name           |
+----------+-----------+-------------+----------------+
|     6771 |         0 |           4 | AC             |
|     6749 |         0 |           4 | Acura USA      |
|     6895 |         0 |           4 | Aixam          |
|     6872 |         0 |           4 | Alfa Romeo     |
|     6853 |         0 |           4 | Alfa Romeo USA |
|     6772 |         0 |           4 | Alpina         |
|     6815 |         0 |           4 | AMC USA        |
|     6854 |         0 |           4 | Anhui Anchi    |
|     6928 |         0 |           4 | Ariel          |
|     6783 |         0 |           4 | ARO            |
+----------+-----------+-------------+----------------+

Here is my Query

INSERT INTO table2 (sku) SELECT product_code FROM table1;

The table1 product_code column has over 2million records inside it and has caused my server to crash during the query.

I know that there must be a better way to do this but I can't figure out how to so would like some assistance if possible please...?

Answer 1

To me your query looks OK.

try breaking the "insert - select" into parts either using some id in the where clause or using limit in the select.

insert 100 records. See how it goes. check your time_out variables. increase accordingly if needed.

Answer 2

You are trying to insert lots of different columns into table_1 but you aren't selecting those out of the first table. So you're inserting one column when you should be inserting 4. I think what you're looking for is:

INSERT INTO table_1(name) SELECT firstname FROM table_2;

If you want to have default values for the other 3 columns, you could easily put them in the select query as well:

INSERT INTO table_1(value_id, parent_id, dropdown_id, name) 
  SELECT  default_id, default_parent_id, default_dropdown_id, firstname
  FROM table_2;

Simply replace the default_ ids with your own defaults, whatever they may be.

Answer 3

The fix was simple,

Just wrap the query inside:

SET AUTOCOMMIT = 0;
SET FOREIGN_KEY_CHECKS = 0;
SET UNIQUE_CHECKS = 0;

# YOUR QUERIES HERE...

SET AUTOCOMMIT = 1;
SET FOREIGN_KEY_CHECKS = 1;
SET UNIQUE_CHECKS = 1;

The the data goes in, only difficulty is the large size of the dataset but breaking it into chunks helped alot.