mysql - get different result using select * and select askid -


that sounds wired,i find when try optimize limit.

askid pk , table has 1.14m rows.
can not give table because it's in production environment.

i try

select askid ask limit 1000000,1;

return 1001747

then try

select * ask limit 1000000,1;

return 1000627

askid has index , influence result, think result should same,isn't it?

select askid ask order askid limit 1000000,1;

return 1000627.

but why order by matters?is there wrong askid index?

the performance different.
first 1 takes 0.2s;
second takes 2s;
third 1 takes 1s;
how optimize , right result?

the mysql version use 5.6.10

sql makes no guarantees in regards row order, chooses whatever makes best plan based on query.

if expect order, specify using order by. , should if you're limiting result set.


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