select unique records from table mysql php

Question

I have notification table, which contains notification_id, type, type_id ... I want to select records which have unique type_id.

I am running this query:

SELECT $cols, DISTINCT type_id FROM notification ORDER BY alert_on ASC

There is something wrong here. What is the way to do it?

If I do like this:

SELECT DISTINCT type_id FROM notification

then it will work. but, i need all the columns from that table...

Answer 1

SELECT $cols,type_id FROM notification GROUP BY type_id ORDER BY alert_on ASC

Answer 2

$query = "SELECT DISTINCT ".$cols." FROM notification ORDER BY alert_on ASC";

SELECT DISTINC的减价不是SELECT，即DISTINCT是SELECT DISTINCT。

Answer 3

您可以尝试使用GROUP BY吗

SELECT $cols, type_id FROM notification GROUP BY type_id ORDER BY alert_on ASC

Answer 4

SELECT DISTINCT column_name,column_name
FROM table_name;