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Editorial Team
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Asked: 2026-05-11T21:06:25+00:00

The other day I found the FOUND_ROWS() ( here ) function in MySQL and

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The other day I found the FOUND_ROWS() (here) function in MySQL and it’s corresponding SQL_CALC_FOUND_ROWS option. The later looks especially useful (instead of running a second query to get the row count).

I’m wondering what speed impact there is by adding SQL_CALC_FOUND_ROWS to a query?

I’m guessing it will be much faster than runnning a second query to count the rows, but will it be a lot different. Also, I have found limiting a query to make it much faster (for example when you get the first 10 rows of 1000). Will adding SQL_CALC_FOUND_ROWS to a query with a small limit cause the query to run much slower?

I know I can test this, but I’m wondering about general practices here.

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  1. Editorial Team

    To calculate SQL_CALC_FOUND_ROWS the query will be execute as if no LIMIT was set, but the result set sent to the client will obey the LIMIT.

    Update: for COUNT(*) operations which would be using only the index, SQL_CALC_FOUND_ROWS is slower (reference).

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