good Sql on Left outer join

Sql  LEFT OUTER JOIN

This is perfect advantage, when the join table didnot have match data on the select.
other data still will show up, and all the join table will be default to null.
until the data will insert and match it to replace it.

left outer join is specail situation will like where.

原文地址:https://www.cnblogs.com/sandy_liao/p/1750226.html