分組如果你把一個rtrim放在SELECT中,並且再次放在GROUP BY中,這是效率低下的,因爲它rtriming兩次,一個在select,一個在group by? e.g ....SQL rtrim選擇並按
SELECT
rtrim(people.FORENAME1)+ ' ' + rtrim(people.SURNAME)AS Full_Name,
FROM
my table
GROUP BY
rtrim(people.FORENAME1)+ ' ' + rtrim(people.SURNAME)
我想你可以簡單地避免在GROUP BY子句中進行修剪,並將其留在SELECT語句中,這應該足以使查詢變得可行,按照@ JNK的回答。 (並且不要忘記在'FROM'子句的某個地方包含'people'表) –