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Editorial Team
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Asked: 2026-06-12T18:43:08+00:00

SELECT MIN(id) FROM mytable WHERE lastname IN(‘Smit’,’Lee’) GROUP BY name Here, for optimise this

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SELECT MIN(id) 
FROM mytable 
WHERE lastname IN('Smit','Lee') 
GROUP BY name

Here, for optimise this query, index needed (will be useful) column lastname right?
and column name also needed index? or only indexed lastname is enough?

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1 Answer

  1. Editorial Team

    Both the proposed indexes should help in your situation, however that depends a lot on the data you have and how costly certain operations are considered by the database engine, depending on if you have duplicates for id, which I suspect you don’t and that’s why it’s called id, but if you do an 2-column index on lastname, id or name, id would also help. Ultimately the query optimizer will decide on the strategy to use to fetch data and that will certainly affect many things…
    I propose you try the following and see which is faster

    • index on lastname – likely
    • index on name – a bit less likely
    • index on lastname, name – most likely
    • index on name, lastname – least likely

    Again it really depends on the data but I marked each of those in the order in which I think they should help most for large amounts of data with unique id’s, if your id’s are not unique try combinations with indexes on id as well.

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