展现精彩：用SQL Server制作曲线图

SQL Server是一款强大的数据库管理系统，具有强大的曲线图制作能力。它可以将记录在数据库中的数据进行可视化并生成各种曲线图，让我们可以更好地展现精彩！下面让笔者根据例子用SQL Server来制作一副曲线图：

第一步：准备数据：在SQL Server中设计一个数据表来保存多条记录，表中有一个柱状图变量和多个曲线图变量。

例如：

建表语句：

create table myTable(

BarVar varchar(15),

CurveVar1 float,

CurveVar2 float,

CurveVar3 float

);

插入数据：

insert into myTable values(‘A’, 10.5, 7.2, 3.2);

insert into myTable values(‘B’, 8.6, 5.6, 2.6);

第二步：绘制曲线图。为绘制曲线图，首先要写一个SQL查询，用来从数据表中提取数据。

SQL查询以下：

SELECT BarVar,

CurveVar1,

CurveVar2,

CurveVar3

FROM myTable

第三步：使用SQL查询取得的数据，在SQL Server中调用曲线图函数构成图形。

如：

SELECT

SeriesName_Test as [SeriesName],

CategoryName_Test as [CategoryName],

Value_Test as [Value],

null as Apple

FROM

(SELECT DISTINCT BarVar AS [CategoryName_Test] , CurveVar1 AS [SeriesName_Test], CurveVar1 AS [Value_Test] FROM myTable) as src

UNION ALL

SELECT

SeriesName_Test as [SeriesName],

CategoryName_Test as [CategoryName],

Value_Test as [Value],

null as Apple

FROM

(SELECT DISTINCT BarVar AS [CategoryName_Test] , CurveVar2 AS [SeriesName_Test], CurveVar2 AS [Value_Test] FROM myTable) as src

UNION ALL

SELECT

SeriesName_Test as [SeriesName],

CategoryName_Test as [CategoryName],

Value_Test as [Value],

null as Apple

FROM

(SELECT DISTINCT BarVar AS [CategoryName_Test] , CurveVar3 AS [SeriesName_Test], CurveVar3 AS [Value_Test] FROM myTable) as src

最后，结合绘图函数把查询的数据可视化，便可构成曲线图。在SQL Server 中，使用Chart Table、chart Function和ChartXML可以实现一些簡單的可视化。

因此，利用SQL Server可轻松实现曲线图的制作，展现精彩！

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