MySQL: SELECT UNIQUE VALUE

Question

In my table I have several duplicates. Ineed to find unique values in mysql table column.

SQL

SELECT column FROM table
WHERE column          


        

Answer 1

try this > select distinct (columnName) from table

Answer 2

Try to use DISTINCT like this:

SELECT DISTINCT mycolumn FROM mytable

EDIT:

Try

select mycolumn, count(mycolumn) c from mytable
group by mycolumn having c = 1

Answer 3

Here is the query that you want!

SELECT column FROM table GROUP BY column HAVING COUNT(column) = 1

This query took 00.34 seconds on a data set of 1 Million rows.

Here is a query for you though, in the future if you DO want duplicates, but NOT non-duplicates...

SELECT column, COUNT(column) FROM table GROUP BY column HAVING COUNT(column) > 1

This query took 00.59 seconds on a data set of 1 Million rows. This query will give you the (column) value for every duplicate, and also the COUNT(column) result for how many duplicates. You can obviously choose not to select COUNT(column) if you don't care how many there are.

You can also check this out, if you need access to more than just the column with possible duplicates... Finding duplicate values in a SQL table

Answer 4

Try this one:

SELECT COUNT(column_name) AS `counter`, column_name 
FROM tablename 
GROUP BY column_name 
WHERE COUNT(column_name) = 1

Have a look at this fiddle: http://sqlfiddle.com/#!9/15147/2/0