Sql Join
xe_document_categories
`category_srl
title
select xe_document.title, xe_document_categories.title from xe_document join xe_document_categories on xe_document.category_srl = xe_document_categories.category_srl
select xe_documents.document_srl, xe_documents.title, xe_document_categories.title from xe_documents left outer join xe_document_categories on xe_documents.category_srl = xe_document_categories.category_srl
select xe_documents.document_srl, xe_documents.title, xe_modules.title from xe_documents left outer join xe_modules on xe_documents.module_srl = xe_modules.module_srl
select d.document_srl, d.title, xe_modules.browser_title , d.content, d.user_id, d.nick_name, d.email_address,d.regdate from xe_documents as d left outer join xe_modules on d.module_srl = xe_modules.module_srl