Datenbank-Fehler

Unknown column 'tl.showflag' in 'where clause'
select distinct tla.* from custThoughtLeadershipAuthor tla inner join custThoughtLeadership tl on (tl.custThoughtLeadershipAuthorID=tla.custThoughtLeadershipAuthorID) where 1 and tla.deleteflag=0 and tl.showflag = 1 and tl.deleteflag = 0 order by tla.sortnumber, tla.author