Query to split thread by post date

[Newtonhead1]

Greetings everyone,

I ran the following query:

update post set threadid=5355 where threadid=3558 and dateline between (unix_timestamp('2006-01-01'), unix_timestamp('2006-01-31'))

Upon which vB returned the following error:

error number: 1064
error desc: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1

Any ideas as to what's not correct in the query?

Thanks,

Newntonhead1