Sqlserver in 实现 参数化查询 XML类型

原文: http://www.cnblogs.com/tangruixin/archive/2012/04/23/2465917.html
1：如果参数是int类型：

declare @a xml
set @a='
<row><id>1</id></row>
<row><id>5</id></row>
<row><id>4</id></row>
<row><id>3</id></row>
<row><id>2</id></row>'
select * from product where id in (
select d.x.value('./id[1]','int') from @a.nodes('/*') as d(x))

2：如果参数是varchar类型：

declare @a xml
set @a='
<row><name>a</name></row>
<row><name>b5</name></row>
<row><name>c4</name></row>
<row><name>d3</name></row>
<row><name>e2</name></row>'
select * from product where pname in (
select d.x.value('./name[1]','varchar(100)') from @a.nodes('/*') as d(x))

以第一个为例写的C#简单方法

public DataSet GetData(List<int> idList) {
System.Text.StringBuilder idXML = new System.Text.StringBuilder();
// 把IdList转换成idxml（后面要用到的xml参数的值）
foreach (var item in idList)
{
idXML.AppendFormat("<row><id>{0}</id></row>",item);
}

System.Text.StringBuilder strSql = new System.Text.StringBuilder();
strSql.Append("select * from product where id in (");
// 解析xml参数@a 取出ID 这里可以认为@a是一个特殊的表
strSql.Append("select d.x.value('./id[1]','int') from @a.nodes('/*') as d(x)");

strSql.Append(")");
SqlConnection con = new SqlConnection("数据库连接字符串");
SqlCommand cmd = new SqlCommand(strSql.ToString(), con);
// 参数赋值
SqlParameter[] para = new SqlParameter[]{
new SqlParameter("@a",SqlDbType.Xml){Value= idXML.ToString()}
};
cmd.Parameters = para;

// 查询
SqlDataAdapter sda = new SqlDataAdapter(cmd);
DataSet ds = new DataSet();
sda.Fill(ds);
return ds;
}