更新时间:2023-01-29 08:50:56
如果列有
唯一索引:否,不会更快
非唯一索引:
Will limiting a query to one result record, improve performance in a large(ish) MySQL table if the table only has one matching result?
for example
select * from people where name = "Re0sless" limit 1
if there is only one record with that name? and what about if name
was the primary key/ set to unique? and is it worth updating the query or will the gain be minimal?
If the column has
a unique index: no, it's no faster
a non-unique index: maybe, because it will prevent sending any additional rows beyond the first matched, if any exist
no index: sometimes