oracle 多表查询

左外连接：

select *  from pms_invoice_register ir  left outer join pms_invoice_client ic on (ir.invoice_register_id =ic.invoice_registerid) where ir.taxpayer_id = 3
等效于：
 select * from pms_invoice_register ir,pms_invoice_client ic where ir.invoice_register_id=ic.invoice_registerid(+) and ir.taxpayer_id = 3
 

右外连接：
 

select * from pms_invoice_register ir,pms_invoice_client ic where ir.invoice_register_id(+)=ic.invoice_registerid and ir.taxpayer_id = 3
 

父子关系的内连接应用：

select * from pms_dictionary child ,pms_dictionary parent where child.parent_dictionary_id = parent.code and parent.code='YYSSM'