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

0 vote377 views1 answer
How to login to mysql in homestead
SQL
4 votes354 views3 answers
Mysql modify foreign key
SQL
1 vote359 views1 answer
Set all the vluses in calumn in sql to false
SQL
0 vote349 views1 answer
Sql row number in result set
SQL
0 vote365 views1 answer
VSCode SQL Server Connection error
SQL
1 vote379 views1 answer
SQl Server Versionen Releases und Build-Nummern
SQL
2 votes739 views1 answer
Oracle virtual column
SQL
0 vote362 views1 answer
Postgres execute multiple sql file from command line
SQL
1 vote350 views1 answer
Select from one table where not on the other
SQL
-1 vote357 views1 answer
Capitole toulouse
SQL