SQL UNION 和 UNION ALL 操作符

　　UNION 操作符用于合并两个或多个 SELECT 语句的结果集。请注意，UNION 内部的 SELECT 语句必须拥有相同数量的列。列也必须拥有相似的数据类型。同时，每条 SELECT 语句中的列的顺序必须相同。SQL UNION 语法，SELECT column_name(s) FROM table_name1

　　UNION

SELECT column_name(s) FROM table_name2

注释：默认地，UNION 操作符选取不同的值。如果允许重复的值，请使用 UNION ALL。

　　SQL UNION ALL 语法

SELECT column_name(s) FROM table_name1 UNION ALL SELECT column_name(s) FROM table_name2另外，UNION 结果集中的列名总是等于 UNION 中第一个 SELECT 语句中的列名。
下面演示一个UNION实例和实例操作后显示数据

select max(dr.ScriptName) as 分类汇总,
sum(dr.ExecuteTrimLenght) as 业务函数总用时,
sum(dr.ExecuteTrimLenght) as 业务函数成功总用时,
0 as 业务函数失败总用时,

dr.IsSucceed as 成功与否
                                        from ScriptExecuteDetailResult as dr left join  ScriptExecuteResut as er on (dr.ser_id = er.id) left join
                                        TaskExecuteResult as ter on (er.ter_id = ter.id) left join 
                                        TaskOrders as eor on (ter.taskOrders_id = eor.id) left join ExecuteResult as er on (dr.ID = er.CaseId)
                                        where dr.isDel = 0  and dr.IsSucceed <> 'ON' 
                                        group by dr.ScriptName

union 
select max(dr.ScriptName) as 分类汇总,
sum(dr.ExecuteTrimLenght) as 业务函数总用时,
sum(dr.ExecuteTrimLenght) as 业务函数成功总用时,
0 as 业务函数失败总用时,

dr.IsSucceed as 成功与否
                                        from ScriptExecuteDetailResult as dr left join  ScriptExecuteResut as er on (dr.ser_id = er.id) left join
                                        TaskExecuteResult as ter on (er.ter_id = ter.id) left join 
                                        TaskOrders as eor on (ter.taskOrders_id = eor.id) left join ExecuteResult as er on (dr.ID = er.CaseId)
                                        where dr.isDel = 0  and dr.IsSucceed <> 'ON' 
and IsSucceed = '成功'
                                        group by dr.ScriptName

union 
select max(dr.ScriptName) as 分类汇总,
sum(dr.ExecuteTrimLenght) as 业务函数总用时,
0 as 业务函数总用时成功,
sum(dr.ExecuteTrimLenght) as 业务函数失败总用时,

dr.IsSucceed  as 成功与否
                                        from ScriptExecuteDetailResult as dr left join  ScriptExecuteResut as er on (dr.ser_id = er.id) left join
                                        TaskExecuteResult as ter on (er.ter_id = ter.id) left join 
                                        TaskOrders as eor on (ter.taskOrders_id = eor.id) left join ExecuteResult as er on (dr.ID = er.CaseId)
                                        where dr.isDel = 0  and dr.IsSucceed <> 'ON' 
and IsSucceed = '失败'
                                        group by dr.ScriptName