MySQL query to select rows where column value is only 0, group by another column?

For this, use group by. Let us first create a table −

mysql> create table DemoTable1344
   -> (
   -> `SequenceId` int NOT NULL AUTO_INCREMENT PRIMARY KEY,
   -> ClientId int,
   -> isMarried tinyint(1)
   -> );
Query OK, 0 rows affected (0.49 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable1344(ClientId,isMarried) values(4567,0);
Query OK, 1 row affected (0.45 sec)
mysql> insert into DemoTable1344(ClientId,isMarried) values(9876,0);
Query OK, 1 row affected (0.16 sec)
mysql> insert into DemoTable1344(ClientId,isMarried) values(5432,1);
Query OK, 1 row affected (0.12 sec)
mysql> insert into DemoTable1344(ClientId,isMarried) values(4567,1);
Query OK, 1 row affected (0.18 sec)
mysql> insert into DemoTable1344(ClientId,isMarried) values(9873,0);
Query OK, 1 row affected (0.15 sec)

Display all records from the table using select statement −

mysql> select * from DemoTable1344;

This will produce the following output −

+------------+----------+-----------+
| SequenceId | ClientId | isMarried |
+------------+----------+-----------+
|          1 |     4567 |         0 |
|          2 |     9876 |         0 |
|          3 |     5432 |         1 |
|          4 |     4567 |         1 |
|          5 |     9873 |         0 |
+------------+----------+-----------+
5 rows in set (0.00 sec)

Following is the query to select rows where column value is only 0, group by another column −

mysql> select SequenceId,ClientId,isMarried
-> from DemoTable1344
-> group by ClientId
-> having isMarried=0;

This will produce the following output −

+------------+----------+-----------+
| SequenceId | ClientId | isMarried |
+------------+----------+-----------+
|          1 |     4567 |         0 |
|          2 |     9876 |         0 |
|          5 |     9873 |         0 |
+------------+----------+-----------+
3 rows in set (0.00 sec)