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For example have in the table the values: green, red, blue, blue, pink, pink, pink, yellow. I would need to return from the colors table only once the blue and the pink. Is there any way to do this?
3 answers
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Use DISTINCT will return without repeating:
SELECT DISTINCT cor FROM Cores;
another unorthodox solution would be to use GROUP BY:
SELECT cor FROM Cores GROUP BY cor;
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That’s right, I’d forgotten.
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I believe that the
GROUP BYbe better, I’ve had absurd performance improvements while changing theDISTINCTby aGROUP BYin the samequeries. Inclusive had aquerywhich took approximately 30 seconds to run, and her process on the process list was at least 28 seconds like "Removing Duplicity" basically, so I took theDISTINCTand put aGROUP BYat the end, and 30 seconds dropped to 0.8 seconds.
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SELECT DISTINCT cor, outra_coluna_se_quiser FROM cores;
I put in the Github for future reference.
The secret there is the DISTINCT. It selects only rows in a single way, without repeating the column value.
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thank you had forgotten this!
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SELECT DISTINCT * FROM cores
You can also use a GROUP BY to group colors:
SELECT DISTINCT * FROM cores GROUP BY cor
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I’m sorry, but it’s not exactly what was answered by Ricardo?
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True, I’m new here I’m still learning to use...
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Start by doing the [tour] then, there gives an overview of how the site works.
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Thanks! I’ll do yes :]
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