mysql - 求sql外行，谁能告诉我这个sql是否高效？

Question

我正在写一个这样的sql

SELECT uid
  FROM search
 WHERE MATCH(product) AGAINST('football basketball')
   AND status=1
 ORDER BY MATCH(product) AGAINST('football basketball') DESC

我在mysql中运行它没问题，但我不确定它是否有效。我想知道这个“ MATCH(product) AGAINST('football Basketball') ”是否跑了两次？

Answer 1

这可能无需担心：

SELECT uid, MATCH(product) AGAINST('football basketball') as imatch
  FROM search
 WHERE imatch 
  AND status=1
 ORDER BY imatch DESC

Answer 2

如果您不想同时选择匹配项，则需要将别名放在 where 子句中。但是别名只运行一次并将结果存储在“变量”中

SELECT uid
FROM search
WHERE MATCH(product) AGAINST('football basketball') as imatch
AND status = 1
ORDER BY imatch DESC