优化sql,返回行数少情况下,NL比hash快好多
摘要:
sql如下select t.id, t.value, tt.sort as sortno from ENGINEERING_TYPE t left join ENGINEERING_TYPE tt on t.parentid = tt.id where t.delete_flag = 0... 阅读全文
posted @ 2015-08-28 16:24 Roc.Sun 阅读(469) 评论(0) 推荐(0) 编辑