How to find unique element in sql

DISTINCT
- select distinct * from employees; ==> 
           retrieves any row if it has at 
           least a single unique column.
- select distinct first_name from employees; ==> 
              retrieves unique names
              from table. (removes duplicates)
- select distinct count(*) from employees;
          retrieve number of unique rows
          if any row has at least a single unique data.

Similar codes

2 votes113 views1 answer
How to delete columns in sql
SQL
0 vote84 views1 answer
Mysql find foreign key references
SQL
57 votes290 views6 answers
Sql alter table
SQL
1 vote138 views1 answer
Alter constraint in sql
SQL
2 votes131 views6 answers
Mysql change timezone
SQL
1 vote119 views1 answer
Illuminate\Database\QueryException SQLSTATE[HY000] [2002] Connection refused (SQL: select * from information_schema.tables where table_schema = laravel and table_name = migrations and table_type = 'BASE TABLE')
SQL
6 votes120 views5 answers
Alter table oracle
SQL
1 vote122 views1 answer
Apex ORA-20999
SQL
0 vote132 views1 answer
SQL SERVER SELECT BETWEEN DATETIME
SQL
6 votes129 views2 answers
Can't connect to local mysql server through socket
SQL