My site get this error:
Can't create/write to file '/tmp/#sql_1c2d_0.MYD' (Errcode: 17)

Please help me! What's this error? And how to do?

Which DB are you operating ?

If it's mysql:

• 17 (EEXIST)
  File exists

http://dev.mysql.com/doc/refman/5.0/...ror-codes.html

As for what to do, I couldn't say. But your db seems to be in a strange state, or have old stale files left over an old instance.

permissions to the /tmp/ folder would be first choice

When I search this error, I found this error says there's existed a file in tmp/ and I (or host) need to empty it. But I can not see any file as error (#sql_1c2d_0.MYD)
there.

I have repaired, checked all table but everything ok