MYSQL: Insert one table into the beginning of another and set the auto_increment

Question

I have php-script, which every 30 sec post the

• current date_time (starts from the 2016-01-27, see below)
• and corresponding some real-time data (Cian)

to the MYSQL-table A (about 100K columns). The table A looks as follows (sql_id is the AUTO_INCREMENT column number):

Also, I have the table B (about 100K columns), which consist of the same data as A , but for the previous period (before the 2016-01-27). So, A starts exactly from the moment, then B was finishing.

Finally I need to have one table, with joined data and:

• name A (it used by php-script and I couldn't change the name inside php)
• B-data should be before A-data (so, B table should be insert into the benining of A and data will be in chronological sequence)
• AUTO_INCREMENT sql_id should be continuous and set to the [sql_id (B) + sql_id (A) + 1]. So, the next sql_id for the php-script will automatically be correct

What will be the best way to do that during 30 sec (before script post the next data)?

Answer 1

The solution is. It could be done, all via sql commands. So its very fast. Every step could be executed independently. But if you have a live system with traffic STEP 4 and STEP 5 should be executed in a transaction.

1. Create a Table with named C with the same structure as A and B

2. Insert the data of B in C but with primary_key = NULL for auto_inc

   INSERT INTO C (sql_id,date_time,cian) SELECT NULL, date_time, cian FROM B;

3. Insert the data of A in C but with primary_key = NULL for auto_inc

   INSERT INTO C (sql_id,date_time,cian) SELECT NULL, date_time, cian FROM A;

4. Delete Table A

   DROP TABLE A;

5. Rename the Table C to A

   ALTER TABLE C RENAME TO A;