MySQL - 如何在分页前计算行数？

Question

I am making a search page to find users. I have que query to find them and actually I can do the pagination with "LIMIT startRow, numberRows". But how could I count the total number of "registers" found before doing the pagination? I would like to add at my search page, the number of the users found in a search.

I need something like: "Page 1 of 100". I actually I have "Page 1" but I don't know how to count the total of results before paginate.

¿Maybe could be necesary execute an extra query with "SELECT COUNT(*)"? ¿Is there another way to count before pagination to avoid another query?

I use two sql queries, one for single word, and another for multiword:

Base sql query (for single word and multi word search):

"SELECT * FROM accounts AS A INNER JOIN profiles AS P ON A.account_id = P.account_id "

Single word condition:

"WHERE A.username LIKE ? OR P.name LIKE ? OR P.name LIKE ? OR P.surname LIKE ? OR P.surname LIKE ? LIMIT ?,?"

Multi word condition:

"WHERE CONCAT(P.name, ' ', P.surname) LIKE ? LIMIT ?,?"

Thanks a lot.

Answer 1

Modify the query like this:

SELECT SQL_CALC_FOUND_ROWS * FROM accounts ... LIMIT ...

This will return the same limited/offset result as before (the first page of results, for example), but if you then immediately send this second query to the server...

SELECT FOUND_ROWS();

The server will return a count of the total number of rows that would have been returned if the LIMIT had not been imposed on the previous query. There's your total number of results.

This will, of course, mean that your initial query takes longer, because the optimizer can't take any shortcuts that might allow it to stop evaluating rows once the LIMIT is satisfied, but in some cases, no such shortcuts are available anyway.

This is the "official" mechanism for doing what you are trying to accomplish.

http://dev.mysql.com/doc/refman/5.7/en/information-functions.html#function_found-rows

Answer 2

You could use do something like this:

SELECT (select count(*) from produtos) as counter, column1, column2, column3, column4 FROM accounts AS A INNER JOIN profiles AS P ON A.account_id = P.account_id WHERE A.username LIKE ? OR P.name LIKE ? OR P.name LIKE ? OR P.surname LIKE ? OR P.surname LIKE ? LIMIT ?,?;

Instead of selecting all (*), you use each column name, and create another column called counter.