MSSQL Order by date with distinct

Question

我在下面有这个查询段，我试图从这个 table 中的日期字段构建 "month-year" 的字符串。从当前月份开始，往后 12 个月，它以正确的顺序出现非常重要。

DECLARE @cols AS NVARCHAR(MAX)
SELECT @cols = STUFF(
(SELECT N',' + QUOTENAME(y) AS [text()]
FROM (SELECT DISTINCT CONVERT(char(3), StartDate, 0) + '-' +  
      RIGHT(CONVERT(varchar, YEAR(StartDate)), 2) AS y 
      FROM Products2
     ) AS Y
--ORDER BY y desc
FOR XML PATH('')),
1, 1, N'')

这个查询没有按正确的顺序提取日期，我想看看你们是否知道任何巧妙的技巧来按正确的顺序提取日期。我可以引入 startDate 列并按它进行排序，但它会引入重复项，因为它可能在同一个月有多个条目。我在这里 http://sqlfiddle.com/#!6/3a500/5

创建了一个示例 table

Answer 1

你可以使用

DECLARE @cols AS NVARCHAR(MAX);

SELECT @cols = STUFF((SELECT N',' + QUOTENAME(y) AS [text()]
                      FROM   (SELECT CONVERT(CHAR(3), StartDate, 0) + '-'
                                     + RIGHT(CONVERT(VARCHAR, YEAR(StartDate)), 2) AS y,
                                     MIN(StartDate)                                AS z
                              FROM   Products2
                              GROUP  BY CONVERT(CHAR(3), StartDate, 0) + '-'
                                        + RIGHT(CONVERT(VARCHAR, YEAR(StartDate)), 2)) AS Y
                      ORDER  BY z
                      FOR XML PATH('')), 1, 1, N'');

SELECT @cols;

SQL Fiddle

Answer 2

如果您正在使用 SQL Server 2012+，您可以使用 FORMAT 函数：

DECLARE @cols AS NVARCHAR(MAX);

;WITH cte AS       -- get only one date per month/year
(
  SELECT MIN(StartDate) AS StartDate
  FROM #Products2 
  GROUP BY YEAR(StartDate),MONTH(StartDate)
)
SELECT @cols = STUFF((SELECT  ',' + QUOTENAME(FORMAT(StartDate, 'MMM-yy'))
                      FROM cte
                      ORDER BY StartDate      
                      FOR XML PATH('')),
                    1, 1, N'');

SELECT @cols;

LiveDemo

输出：

╔══════════════════════════════════════════════════════════════════════════════════════════════════════════════════════╗
║                                                        result                                                        ║
╠══════════════════════════════════════════════════════════════════════════════════════════════════════════════════════╣
║ [Dec-15],[Jan-16],[Feb-16],[Mar-16],[Apr-16],[May-16],[Jun-16],[Jul-16],[Aug-16],[Sep-16],[Oct-16],[Nov-16],[Dec-16] ║
╚══════════════════════════════════════════════════════════════════════════════════════════════════════════════════════╝

Answer 3

您似乎刚刚获得 month/year，因此我们可以截断到该月的第一天并将其包含在查询中。

DATEADD(month, DATEDIFF(month, 0, StartDate), 0)  monthStart

现在我们可以通过它来订购了：

DECLARE @cols AS NVARCHAR(MAX);


 SELECT @cols = STUFF(
  (SELECT N',' + QUOTENAME(y) AS [text()]
  FROM (
        SELECT DISTINCT CONVERT(char(3), StartDate, 0) + '-' +  
        RIGHT(CONVERT(varchar, YEAR(StartDate)), 2) AS y, 
        DATEADD(month, DATEDIFF(month, 0, StartDate), 0)  monthStart
        FROM Products2
       ) AS Y
  ORDER BY monthStart
  FOR XML PATH('')),
1, 1, N'');

select @cols;

这是输出：

[Dec-15],[Jan-16],[Feb-16],[Mar-16],[Apr-16],[May-16],[Jun-16],[Jul-16],[Aug-16],[Sep-16],[Oct-16],[Nov-16],[Dec-16]

这就是您要找的吗？这是 fiddle： http://sqlfiddle.com/#!6/3a500/67

更好的是，只需 select 不同的月份开始日期，然后仅对其进行字符串转换。

   DECLARE @cols AS NVARCHAR(MAX);

     SELECT @cols = STUFF(
      (SELECT N',' + QUOTENAME(CONVERT(char(3), monthStart, 0) + '-' +  
            RIGHT(CONVERT(varchar, YEAR(monthStart)), 2)) AS [text()]
      FROM (
            SELECT DISTINCT 
                DATEADD(month, DATEDIFF(month, 0, StartDate), 0)  monthStart
      FROM Products2
           ) AS Y
      ORDER BY monthStart
      FOR XML PATH('')),
    1, 1, N'');

    select @cols;

这是 fiddle： http://sqlfiddle.com/#!6/3a500/72

MSSQL Order by date with distinct

MSSQL Order by date with distinct

sql

tsql

sql-server

sql-order-by