MySQL：ORDER BY子句中的最大列数？

Question

SELECT DISTINCT city, street, street_type, house
FROM table
WHERE street LIKE '%Ololo%'
ORDER BY city, street, street_type, CHAR_LENGTH(house), house

Found that CHAR_LENGTH(house) doesn't sort by it if placed on 4th position in ORDER BY. It starts to sory by CHAR_LENGTH(house) only if it's placed on 1..3 position. city, street, street_type all contain the same data in this example. Tried to CONCAT first columns in ORDER BY: doesn't help. house contains chars that's why I used CHAR_LENGTH(house), house

Answer 1

If house is char , try CHAR_LENGTH(TRIM(house)) to remove trailing spaces

Otherwise, it means that city, street, street_type are actually different: these are breaking the sort. When it goes back to short again, one of these changes