sql - Why subquery returns <= Error Occurs -

my sql query is

alter procedure [dbo].[proc_project_cat_d_list]     @user_id bigint=null, @cat_id bigint=null, @dept_id bigint=null          if(@cat_id > 0 )     begin       select detail_id, detail_code, spec_1, spec_2, spec_3, spec_4, cat_id       project_cat_details       cat_id=@cat_id       end     else     begin        if(@dept_id null)        select @dept_id=dept_id         employee_master        emp_id=@user_id         create table #temp_dept ( dept_id bigint, dept_name varchar(100), parent_dept bigint )       insert #temp_dept       ( dept_id, dept_name, parent_dept )       exec [dept_list] @dept_id, 1,  @user_id          select pcd.detail_id, pcd.detail_code,isnull(spec_1,'')+ ' ' +isnull(spec_2,'') specsfi, pcd.spec_1, pcd.spec_2, pcd.spec_3, pcd.spec_4, pcd.cat_id,p.project_name,pc.cat_name,       p.project_id       #temp_dept t, projects p, project_cat pc, project_cat_details pcd        t.dept_id=p.dept_id , p.project_id=pc.project_id , pc.cat_id=pcd.cat_id  , deleted !=1   order   pcd.detail_id desc     drop table #temp_dept      end   

i have added condition in sql query deleted!=0 error comes

based on comment, seems using version prior sql server 2005.

comparison operator != supports on sql server 2005 , above. try changing <> operator.