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Count from two tables and give combined count of string in MySQL?
To count, use the MySQL COUNT(*). However, with UNION ALL you would be able to get a combined count of string. Let us first create a table −
mysql> create table DemoTable1 ( Name varchar(20) ); Query OK, 0 rows affected (0.49 sec)
Insert some records in the table using insert command. We are inserting string values in the first table −
mysql> insert into DemoTable1 values('Chris');
Query OK, 1 row affected (0.14 sec)
mysql> insert into DemoTable1 values('Robert');
Query OK, 1 row affected (0.12 sec)
mysql> insert into DemoTable1 values('Mike');
Query OK, 1 row affected (0.13 sec)
mysql> insert into DemoTable1 values('Robert');
Query OK, 1 row affected (0.10 sec)Display all records from the table using select statement −
mysql> select *from DemoTable1;
This will produce the following output −
+--------+ | Name | +--------+ | Chris | | Robert | | Mike | | Robert | +--------+ 4 rows in set (0.00 sec)
Following is the query to create the second table. We are inserting string values in the second table as well −
mysql> create table DemoTable2 ( Name varchar(40) ); Query OK, 0 rows affected (0.43 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable2 values('Robert');
Query OK, 1 row affected (0.11 sec)
mysql> insert into DemoTable2 values('Chris');
Query OK, 1 row affected (0.10 sec)
mysql> insert into DemoTable2 values('Robert');
Query OK, 1 row affected (0.31 sec)
mysql> insert into DemoTable2 values('David');
Query OK, 1 row affected (0.13 sec)Display all records from the table using select statement −
mysql> select *from DemoTable2;
This will produce the following output −
+--------+ | Name | +--------+ | Robert | | Chris | | Robert | | David | +--------+ 4 rows in set (0.00 sec)
Following is the query to get the combined count of string values from both the tables using COUNT(*) and UNION ALL −
mysql> select tbl.Name,count(*) as Total_Count from ( select Name from DemoTable1 UNION ALL select Name from DemoTable2 )tbl group by tbl.Name;
This will produce the following output. The combined count is displayed in a new column “Total_Count” −
+--------+-------------+ | Name | Total_Count | +--------+-------------+ | Chris | 2 | | Robert | 4 | | Mike | 1 | | David | 1 | +--------+-------------+ 4 rows in set (0.00 sec)
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