如何计算具有不同记录的查询？

Question

I have a query with DISTINCT columns.

SELECT 
    DISTINCT column_1
    column_2,
    column_3,
    column_4,
    column_5,
    column_6,
    column_7,
    column_8,
    column_9
FROM 
    my_table 
WHERE 
    column_4 IN(some array) 
    and ... 
    order by column_1, column_2

This query is correct which returns some 1000 records. Now I need to find out total number of records using count.

I have tried select count(DISTINCT column_1) but the count record is not 1000.

I can apply count the records from PHP but I am looking to do it from query itself.

Can anybody please teach me how to write count query?

Answer 1

COUNT(DISTINCT column_1) only counts the number of distinct column_1 values. To get the number of results that are in your query, you need to apply COUNT(DISTINCT...) to all the columns:

SELECT COUNT(DISTINCT column_1, column_2, column_3, column_4, ... column_9)
FROM my_table 
WHERE ...

Note that this is a MySQL extension to SQL and will not work on other DBMS.