Merge two tables with union in MySQL?

To merge two tables with UNION, you can use create table select statement. Following is the syntax −

create table yourNewTableName
select * from yourFirstTableName
UNION
select * from yourSecondTableName;

Let us first create a table. Following is the query −

mysql> create table FirstTable
   -> (
   -> Id int,
   -> PersonName varchar(20)
   -> );
Query OK, 0 rows affected (2.10 sec)

Following is the query to insert some records in the table using insert command −

mysql> insert into FirstTable values(10,'Larry');
Query OK, 1 row affected (0.12 sec)

mysql> insert into FirstTable values(20,'David');
Query OK, 1 row affected (0.22 sec)

Following is the query to display all records from the table using select statement −

mysql> select * from FirstTable;

This will produce the following output −

+------+------------+
| Id   | PersonName |
+------+------------+
| 10   | Larry      |
| 20   | David      |
+------+------------+
2 rows in set (0.00 sec)

Following is the query to create the second table −

mysql> create table SecondTable
   -> (
   -> Id int,
   -> PersonName varchar(20)
   -> );
Query OK, 0 rows affected (0.91 sec)

Following is the query to insert some records in the table using insert command −

mysql> insert into SecondTable values(30,'Chris');
Query OK, 1 row affected (0.17 sec)

mysql> insert into SecondTable values(40,'Robert');
Query OK, 1 row affected (0.15 sec)

Let us now display all records from the table using the select statement −

mysql> select *from SecondTable;

This will produce the following output −

+------+------------+
| Id   | PersonName |
+------+------------+
| 30   | Chris      |
| 40   | Robert     |
+------+------------+
2 rows in set (0.00 sec)

Now, create a table from merging two tables (FirstTable + SecondTable) with union −

mysql> create table MergeBothTableDemo
   -> select * from FirstTable
   -> UNION
   -> select * from SecondTable;
Query OK, 4 rows affected (0.86 sec)
Records: 4 Duplicates: 0 Warnings: 0

Let us check the new table records. Following is the query −

mysql> select * from MergeBothTableDemo;

This will produce the following output −

+------+------------+
| Id   | PersonName |
+------+------------+
| 10   | Larry      |
| 20   | David      |
| 30   | Chris      |
| 40   | Robert     |
+------+------------+
4 rows in set (0.00 sec)