帝国cms常常应用的SQL语句

1.复制tags字段内容到keyboard，当keyboard为空的时候：

update [!db.pre!]ecms_news_data_1 a, [!db.pre!]ecms_news b set b.keyboard=a.infotags where a.id=b.id and b.keyboard='';

2.添加tags字段内容到keyboard：

update [!db.pre!]ecms_news_data_1 a, [!db.pre!]ecms_news b set b.keyboard=ｃｏｎｃａｔ(b.keyboard,',',a.infotags) where a.id=b.id and b.keyboard<>'' and a.infotags<>'';

3.如果副表中keyid（