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Select a value from MySQL database only if it exists only once from a column with duplicate and non-duplicate values
Let us first create a table −
mysql> create table DemoTable723 (Value int); Query OK, 0 rows affected (0.58 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable723 values(100); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable723 values(200); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable723 values(200); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable723 values(100); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable723 values(300); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable723 values(400); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable723 values(400); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable723 values(600); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable723 values(400); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable723 values(200); Query OK, 1 row affected (0.17 sec)
Display all records from the table using select statement −
mysql> select *from DemoTable723;
This will produce the following output -
+-------+ | Value | +-------+ | 100 | | 200 | | 200 | | 100 | | 300 | | 400 | | 400 | | 600 | | 400 | | 200 | +-------+ 10 rows in set (0.00 sec)
Following is the query to select a value from MySQL database only if it exists once from a column with duplicate and non-duplicate values −
mysql> select *from DemoTable723 group by Value having count(Value)=1;
This will produce the following output -
+-------+ | Value | +-------+ | 300 | | 600 | +-------+ 2 rows in set (0.00 sec)
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