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Asked: 2026-06-16T02:52:19+00:00

Sorry, don’t know how to formulate this question. I’ll try to explain. Here’s a

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Sorry, don’t know how to formulate this question. I’ll try to explain. Here’s a query:

SELECT CONCAT(uno, due, tre) AS smth ... HAVING smth LIKE ...

It allows me to perform operations on aggregated multi-column data and, while it works ok, i don’t want the results of “smth” column to actually be selected and returned. Is it possible o do something like this?:

SELECT ... WHERE CONCAT(uno, due, tre) AS smth LIKE '...' OR smth LIKE '...' ...

Or does mysql already optimize a query with multiple identical concats to not concatinate the same data twice?

I hope the question is clear. Thank you for your thoughts.

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1 Answer

  1. Editorial Team

    Directly use the desired expression in the relevant WHERE or HAVING clause:

    SELECT
  -- etc.
HAVING CONCAT(uno, due, tre) LIKE '...'
    OR CONCAT(uno, due, tre) LIKE '...'
  -- etc.

    MySQL only evaluates deterministic functions given the same arguments once per query, so despite the verbosity of the query it is no less efficient (save for a negligible amount of parsing).

    Alternatively, you could perform an outer select on your query to only return the columns of interest:

    SELECT ... FROM (
  SELECT CONCAT(uno, due, tre) AS smth ... HAVING smth LIKE ...
) t
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