Error in query, Please check it.Unknown column 'literature' in 'where clause'<br>select DISTINCT(p.lit_subcat_id) , c.cat_name,c.cat_url from b_literature_collection p,b_category c, t_issue_content T where  c.cat_id=p.lit_subcat_id and p.lit_cat_id=27 and T.lit_id=p.lit_id and T.issue_id='109/literature-collection/2/41' and p.lit_subcat_id not in (select DISTINCT(post_subcat_id) from b_posts px, t_issue_content tx where  post_cat_id=27 and px.post_id=tx.article_id and tx.issue_id=109/literature-collection/2/41)