Question

我有以下两个表：

Table "Center":
CenterKey   CenterName
---------   -----------
Center1     CenterName1
Center2     CenterName2
Center3     CenterName3
Center4     CenterName4
Center5     CenterName5
Center6     CenterName6
Center7     CenterName7
Center8     CenterName8

Table "Log":
CenterKey   Date        Value
---------   --------    -----
Center1     6/1/2014    10
Center2     6/3/2014    20
Center1     7/2/2014    30
Center3     7/3/2014    40
Center4     7/5/2014    50
Center5     7/8/2014    60
Center6     8/3/2014    70

我有兴趣创建一个视图，比如说“MyView”，如果我指定一个日期范围，它将返回其CenterKey不在日期范围内的CenterNames。

例如，如果我这样做

SELECT CenterName FROM MyView WHERE Date>='6/1/2014' AND Date <='6/30/2014'

我想要这个结果：

CenterName 
----------
CenterName3
CenterName4
CenterName5
CenterName6
CenterName7
CenterName8

如果我这样做

SELECT CenterName FROM MyView WHERE Date>='7/1/2014' AND Date <='7/31/2014'

我想要这个结果：

CenterName 
----------
CenterName2
CenterName6
CenterName7
CenterName8

如果我这样做

SELECT CenterName FROM MyView WHERE Date>='6/3/2014' AND Date <='7/5/2014'

我想要这个结果：

CenterName5
CenterName6
CenterName7
CenterName8

有人可以帮我创建MyView吗？

Answer 1

以下查询应该执行您想要的操作：

select c.centername
from center c left outer join
     log l 
     on l.centerkey = c.centerkey
group by c.centername
having sum(l.Date >='2014-07-01' AND .Date <='2014-07-31') = 0;

我无法想出一种方法可以轻松地将其合并到带有where子句的视图中。

替代配方并没有真正帮助：

select c.centername
from center c 
where not exists (select 1
                  from log l
                  where l.centerkey = c.centerkey and
                        l.Date >= '2014-07-01' AND l.Date <='2014-07-31'
                 );

编辑：

如果您有日历表，则可以执行以下操作：

select c.centername, ca.dte
from calendar ca cross join
     center c left outer join
     log l 
     on l.centerkey = c.centerkey and ca.dte = l.date
where l.date is null;

如果您将其放在带有where的视图中，则当中心可用时，您将获得该范围内每个日期的单独行。

Answer 2

SELECT CenterName 
FROM Center 
WHERE CenterKey NOT IN 
(     SELECT CenterKey 
      FROM Log 
      WHERE Date>='6/1/2014' AND Date <='6/30/2014' 
)

Answer 3

您只需加入表格：

SELECT Centername FROM Center AS c NATURAL JOIN Log as L WHERE Date>='6/3/2014' AND Date <='7/5/2014'

Answer 4

使用参数查看

最终SQL查询（http://sqlfiddle.com/#!2/570cb8/1）：

SELECT *
FROM
  (SELECT @startd:='2014-6-1', @endd:='2014-6-30') p , MyView;

查看功能：

create function startd() returns DATE DETERMINISTIC NO SQL return @startd;
create function endd() returns DATE DETERMINISTIC NO SQL return @endd;

create view MyView as
select centername from center c where not exists
(
  select 1 from log l where l.centerkey = c.centerkey AND
  d between startd() AND endd()
);

<强>参考

Can I create view with parameter in MySQL?

选择日期范围内的补充记录

4 个答案:

使用参数查看