标签: sql-order-by

博主

blogger_id
1 
2
3

2.帖子

post_from_blogger_id
1 
1
1
2
2
3

正如你可以看到博客№1发布超过其他人和博客№3少.问题是如何构建一个选择所有博主的查询,并根据帖子的数量对它们进行排序？

我想用两列对我的产品表进行排序:prod_price和prod_name.

SELECT prod_id, prod_price, prod_name
FROM Products
ORDER BY prod_price, prod_name;

如何在这里完成排序？我认为它首先发生prod_price,然后发生prod_name.此外,上述查询与此不同如何:

SELECT prod_id, prod_price, prod_name
FROM Products
ORDER BY prod_name;

我的产品表如下:

CREATE TABLE Products
(
  prod_id    char(10)      NOT NULL ,
  vend_id    char(10)      NOT NULL ,
  prod_name  char(255)     NOT NULL ,
  prod_price decimal(8,2)  NOT NULL ,
  prod_desc  text          NULL 
);

我怎样才能确定我的结果集有a第一个和b第二个？这将有助于我解决一个棘手的订购问题.

这是我正在做的简化示例:

SELECT a FROM A LIMIT 1 
UNION 
SELECT b FROM B LIMIT 1;

我的目标是执行两个不同的查询,然后将它们组合起来.
我的代码是:

SELECT * FROM some tables WHERE ... ORDER BY field1 LIMIT 0,1 
UNION   
SELECT * FROM some tables WHERE ...

我收到以下错误:

#1221 - UNION和ORDER BY的使用不正确

重要的是ORDER BY仅用于第一个查询.我该如何执行此任务？

知道为什么LINQ OrderBy不能在下面的代码中工作,(没有错误,但方法不排序......)

首先是我自己的类型

public class IQLinksView
    {
        public int id { get; set; }
        public int catid { get; set; }
        public int? viewed {get;set;}
        public string name {get;set;}
        public string desc {get;set;}
        public string url {get;set;}
        public string pic {get;set;}
        public string cat {get;set;}
    }

然后查询:

IQueryable<IQLinksView> newView = 
              from links in this.emContext.tbl_otherlinks
              select new IQLinksView { id = links.pklinkid, catid =
              links.tbl_catgeory.pkcategoryid, viewed = links.linkviewed, name = links.linkname, 
              desc = links.linkdesc, pic = links.linkpicture,   url = links.linkurl, cat …

我有以下JOIN查询:

SELECT
    table1.*, 
    table2.*
FROM 
    Table1 AS table1 
LEFT JOIN 
    Table2 AS table2 
USING 
    (col1)
LEFT JOIN 
    Table3 as table3 
USING 
    (col1) 
WHERE 
    3963.191 * 
    ACOS(
    (SIN(PI() * $usersLatitude / 180) * SIN(PI() * table3.latitude / 180)) 
    +
    (COS(PI() * $usersLatitude / 180) * COS(PI() * table3.latitude / 180) * COS(PI() * table3.longitude / 180 - PI() * 37.1092162 / 180))
    ) <= 10 
AND 
    table1.col1 != '1' 
AND 
    table1.col2 LIKE 'A' 
AND 
    (table1.col3 LIKE 'X' OR table1.col3 LIKE 'X-Y') …

如果我写

select ename, to_char(hiredate,'fmDay') as "Day" order by "Day";

然后根据Day对结果进行排序; 从星期五,然后是周一和上周三,就像按字符排序一样.

但是我想在一周之前对它进行排序; 从周一到周日.

我们希望在使用Visual Studio DataSet Designer创建的查询或存储过程的"Order By"子句中使用参数.

例:

  FROM TableName
 WHERE (Forename LIKE '%' + @SearchValue + '%') OR
       (Surname LIKE '%' + @SearchValue + '%') OR
       (@SearchValue = 'ALL')
ORDER BY @OrderByColumn

显示此错误:

Variables are only allowed when ordering by an expression referencing 
a column name.

什么是使用DOMAIN名称片段对具有一列电子邮件地址的表进行排序的最短和/或最有效的SQL语句？

这基本上忽略了电子邮件地址中"@"之前的任何内容,并且不区分大小写.让我们忽略这个国际化的域名.

目标是:mySQL,MSSQL,Oracle

来自的样本数据 TABLE1

id   name           email 
------------------------------------------
 1   John Doe       johndoe@domain.com
 2   Jane Doe       janedoe@helloworld.com
 3   Ali Baba       ali@babaland.com
 4   Foo Bar        foo@worldof.bar.net
 5   Tarrack Ocama  me@am-no-president.org

通过电子邮件订购
SELECT * FROM TABLE1 ORDER BY EMAIL ASC

id   name           email 
------------------------------------------
 3   Ali Baba       ali@babaland.com
 4   Foo Bar        foo@worldof.bar.net
 2   Jane Doe       janedoe@helloworld.com
 1   John Doe       johndoe@domain.com
 5   Tarrack Ocama  me@am-no-president.org

按域名排序
SELECT * FROM TABLE1 ORDER BY ?????? ASC

id   name           email 
------------------------------------------
 5   Tarrack Ocama  me@am-no-president.org
 3 …

以下查询在几乎每个数据库(提供或获取虚拟表)中都非常有效dual,包括Oracle:

select 'A' as x from dual union all
select 'B'      from dual
order by x asc

返回:

| X |
|---|
| A |
| B |

现在这个查询仍然是非常标准的SQL,但不适用于Oracle

select 'A' as x from dual union all
select 'B'      from dual union all
select 'C'      from dual
order by x asc

我越来越

ORA-00904: "X": invalid identifier

但是,这有效:

select 'A' as x from dual union all
select 'B' as x from dual union all …