How to get row count of two tables in different databases in a single query?

For this, you can use aggregate function COUNT(*). Let us first create a table in let’s say database “web” −

mysql> create table DemoTable1    -> (    -> Value int    -> ); Query OK, 0 rows affected (0.60 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable1 values(10); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable1 values(20); Query OK, 1 row affected (0.15 sec)

Display all records from the table using select statement −

mysql> select *from DemoTable1;

Output

This will produce the following output −

+-------+ | Value | +-------+ |    10 | |    20 | +-------+ 2 rows in set (0.00 sec)

Following is the query to create second table in another database with the name “test” −

mysql> create table DemoTable2    -> (    -> Value int    -> ); Query OK, 0 rows affected (0.68 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable2 values(100); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable2 values(200); Query OK, 1 row affected (0.15 sec)

Display all records from the table using select statement −

mysql> select *from DemoTable2;

Output

This will produce the following output −

+-------+ | Value | +-------+ |100    | |200   | +-------+ 2 rows in set (0.00 sec)

Following is the query to get row count of 2 tables in different databases in a single query −

mysql> select -> ( -> select count(*) from web.DemoTable1) AS Table1Count, -> (select count(*) from test.DemoTable2) AS Table2Count;

Output

This will produce the following output −

+---------------+---------------+ | Table1Count | Table2Count | +---------------+---------------+ | 2 | 2 | +---------------+---------------+ 1 row in set (0.06 sec)