Question

我编写了一个SQL Server查询，它返回几个select语句的并集。查询返回我期望的数据。

但它正在做的一个意想不到的事情是它按字母顺序对数据进行排序。但是，我想要的是第一个表的数据应该出现在顶部，第二个表的数据应该出现在第二个，依此类推。

有人可以帮我吗？

select employeename from employeetable where employeename like 'vik%'
union
select employeename from employeetable where employeename like '% vik%'
union
select employeename from EmployeeTable where employeename like '%vik%' and
                                             employeename not like 'vik%' and
                                             employeename not like '% vik%'

Answer 1

您可以在不union的情况下执行此操作：

select employeename
from employeetable
where employeename like '%vik%'
order by (case when employeename like 'vik%' then 1
               when employeename like '% vik%' then 2
               else 3
          end);

如果您可以在employeename中复制employeetable，则可以使用group by删除重复项：

select employeename
from employeetable
where employeename like '%vik%'
group by employeename
order by (case when employeename like 'vik%' then 1
               when employeename like '% vik%' then 2
               else 3
          end);

Answer 2

为表序列添加一列

select employeename, 1 as my_order from employeetable where employeename like 'vik%'
union
select employeename, 2 from employeetable where employeename like '% vik%'
union
select employeename, 3 from EmployeeTable where employeename like '%vik%' and employeename not like 'vik%' and employeename not like '% vik%'
order by my_order asc, empleemployeename asc;

Answer 3

select employeename, a as _order from employeetable where employeename like 'vik%'
union
select employeename, b as _order from employeetable where employeename like '% vik%'
union
select employeename, c as _order from EmployeeTable where employeename like '%vik%' and employeename not like 'vik%' and employeename not like '% vik%'
order by my_order asc, empleemployeename asc;

Answer 4

select 1 s,employeename from employeetable where employeename like 'vik%'
union
select 2 s, semployeename from employeetable where employeename like    '%vik%'
union
select 3 s,employeename from EmployeeTable where employeename like '%vik%' and employeename not like 'vik%' and employeename not like '% vik%'     
order by s;

你的3个表中的进一步排序顺序是未定义的，如果没有指定，可能会变成任何东西

使表的联合按照它们的应用顺序出现

4 个答案: