SQL Server查询日期发行

Question

这正确执行：（这是奇怪的，我需要的日期用'它实际上执行）

DECLARE 
@cols AS NVARCHAR(MAX), 
@query AS NVARCHAR(MAX); 

select @cols = STUFF((SELECT distinct ',' + QUOTENAME(c.statcolumnname) FROM [85137_PHY_Long_PG] c FOR XML PATH(''), TYPE).value('.', 'NVARCHAR(MAX)'),1,1,'') 

set @query = 'SELECT statdate, ' + @cols + ' from 
     (
      select statdate, statcolumnname, statcolumnvalue 
      from [85137_PHY_Long_PG] 
     ) x 
     pivot 
     (
      min(statcolumnvalue) 
      for statcolumnname in (' + @cols + ') 
     ) p WHERE statdate BETWEEN ''2012-04-01 12:15:00'' AND ''2012-04-01 12:45:00''  ORDER BY statdate' 

execute(@query) 

现在我想用变量替换日期：

DECLARE 
@cols AS NVARCHAR(MAX), 
@query AS NVARCHAR(MAX), 
@from AS NVARCHAR(MAX), 
@to AS NVARCHAR(MAX); 

set @from = '2012-04-01 12:15:00' 
set @to = '2012-04-01 12:45:00' 

select @cols = STUFF((SELECT distinct ',' + QUOTENAME(c.statcolumnname) FROM [85137_PHY_Long_PG] c FOR XML PATH(''), TYPE).value('.', 'NVARCHAR(MAX)'),1,1,'') 

set @query = 'SELECT statdate, ' + @cols + ' from 
     (
      select statdate, statcolumnname, statcolumnvalue 
      from [85137_PHY_Long_PG] 
     ) x 
     pivot 
     (
      min(statcolumnvalue) 
      for statcolumnname in (' + @cols + ') 
     ) p WHERE statdate BETWEEN ''+@from+'' AND ''+@to+'' ORDER BY statdate' 

execute(@query) 

我得到以下错误：转换把字符串时SMALLDATETIME数据类型

更改失败where语句到t他以下几点：

WHERE statdate BETWEEN ''+convert(smalldatetime,@from)+'' AND ''+convert(smalldatetime,@to)+'' ORDER BY statdate' 

仍然给我相同的错误，似乎就是无法更换日期作为变量

Answer 1

“”是不奇怪;它是一种在varchars中启用撇号的符号。

当连接时，确保你没有尝试连接（n）varchars和（n）个字符以外的任何东西，因为Sql Server会尝试将它们转换为其他数据类型;在你的情况下，在smalldatetime。您可以通过在连接前/连接期间将参数日期显式转换为nvarchars来避免此问题，但更好的解决方案是使用sp_executesql和参数。

如果你把里面的查询参数：

set @query = 'SELECT statdate, ' + @cols + ' from 
    (
     select statdate, statcolumnname, statcolumnvalue 
     from [85137_PHY_Long_PG] 
    ) x 
    pivot 
    (
     min(statcolumnvalue) 
     for statcolumnname in (' + @cols + ') 
    ) p WHERE statdate BETWEEN @from AND @to ORDER BY statdate' 

你可以用参数来执行：

exec sp_executesql @query, N'@from datetime, @to datetime', @from=@from_variable, @to=@to_variable 

凡@from_variable和@to_variable是一批早期定义的日期时间变量。

UPDATE：

如果你的最终目标是在存储过程来包装这个代码，这里是一个模板：

create proc MyProc (@dateFrom smalldatetime, @dateTo smalldatetime) 
as 
DECLARE 
@cols AS NVARCHAR(MAX), 
@query AS NVARCHAR(MAX); 

select @cols = STUFF((SELECT distinct ',' + QUOTENAME(c.statcolumnname) 
    FROM [85137_PHY_Long_PG] c 
    FOR XML PATH(''), TYPE).value('.', 'NVARCHAR(MAX)'),1,1,'') 
set @query = 'SELECT statdate, ' + @cols + ' from 
    (
     select statdate, statcolumnname, statcolumnvalue 
     from [85137_PHY_Long_PG] 
    ) x 
    pivot 
    (
     min(statcolumnvalue) 
     for statcolumnname in (' + @cols + ') 
    ) p WHERE statdate BETWEEN @from AND @to ORDER BY statdate' 

exec sp_executesql @query, N'@from smalldatetime, @to smalldatetime', @from=@dateFrom, @to=@dateTo 

Answer 2

。由此解决方案：

DECLARE 
@cols AS NVARCHAR(MAX), 
@query AS NVARCHAR(MAX), 
@internal_fromdate AS SMALLDATETIME, 
@internal_todate AS SMALLDATETIME; 

select @cols = STUFF((SELECT distinct ',' + QUOTENAME(c.statcolumnname) FROM [85137_PHY_Long_PG] c FOR XML PATH(''), TYPE).value('.', 'NVARCHAR(MAX)'),1,1,'') 

set @internal_fromdate = '2012-04-01 12:15:00'; 
set @internal_todate = '2012-04-01 12:45:00'; 

set @query = 'SELECT statdate, ' + @cols + ' from 
     (
      select statdate, statcolumnname, statcolumnvalue 
      from [85137_PHY_Long_PG] 
     ) x 
     pivot 
     (
      min(statcolumnvalue) 
      for statcolumnname in (' + @cols + ') 
     ) p WHERE statdate BETWEEN @FromDate AND @ToDate ORDER BY statdate' 

exec sp_executesql @query, N'@FromDate SMALLDATETIME, @ToDate SMALLDATETIME', @FromDate=@internal_fromdate, @ToDate=@internal_todate 

UPDATE

好吧，我已经尝试了以下变化：

create proc MyProc9 (@tableName varchar,@dateFrom smalldatetime, @dateTo smalldatetime) 
AS 
DECLARE 
@cols AS NVARCHAR(MAX), 
@query AS NVARCHAR(MAX); 

select @cols = STUFF((SELECT distinct ',' + QUOTENAME(c.statcolumnname) 
FROM [85137_PHY_Long_MP] c 
FOR XML PATH(''), TYPE).value('.', 'NVARCHAR(MAX)'),1,1,'') 
set @query = 'SELECT statdate, ' + @cols + ' from 
(
    SELECT statdate, statcolumnname, statcolumnvalue 
    from @table 
) x 
pivot 
(
    min(statcolumnvalue) 
    for statcolumnname in (' + @cols + ') 
) p WHERE statdate BETWEEN @from AND @to ORDER BY statdate' 

exec sp_executesql @query, N'@table varchar,@from smalldatetime, @to smalldatetime', @table=@tableName,@from=@dateFrom, @to=@dateTo 

错误：必须声明表变量 “@table”。

在@query字符串中尝试了'+ @ tableName +'：'8'附近的语法错误。

在@query字符串中尝试'+ QUOTENAME（@tableName）+'：无效的对象名称'8'。

在@query字符串中尝试['+ @ tableName +']：无效的对象名称'8'。

在@query字符串中尝试了QUOTENAME（@table）：无效的对象名称'8'。

在@query字符串中尝试[85137_PHY_Long_MP]：正常工作，只是想替换它。

在@query字符串中尝试[@tableName]：无效的对象名称'@tableName'。

在@query字符串中尝试@tableName：必须声明表变量“@tableName”。

我不明白如何解决问题