/* 这一部分和上面一样 */　　　　　　SQLRETURN l_uiReturn = SQLAllocHandle(SQL_HANDLE_STMT,m_hDatabaseConnection,&m_hStatement);if (l_uiReturn != SQL_SUCCESS && l_uiReturn != SQL_SUCCESS_WITH_INFO){return l_oRetval;}CString l_cstrSql;l_cstrSql.Format(_T("SELECT [float] FROM [数据源名称].[所属者].[data] ORDER BY [float] DESC"));l_uiReturn = SQLExecDirect(m_hStatement,l_cstrSql.GetBuffer(),SQL_NTS);if (l_uiReturn != SQL_SUCCESS && l_uiReturn != SQL_SUCCESS_WITH_INFO){return l_oRetval;}/* 该代码段用于配置当前语句相关数据列的数据格式 */ //这里开始进入重点 #pragma regionSQLHDESC l_hDesc; //第四种句柄出现了l_uiReturn = SQLGetStmtAttr(m_hStatement, SQL_ATTR_APP_ROW_DESC,&l_hDesc, 0, NULL);//获得SQL语句的属性if (l_uiReturn != SQL_SUCCESS && l_uiReturn != SQL_SUCCESS_WITH_INFO){return l_oRetval;}/* Float数据格式，对应数据库中设置格式为DECIMAL(5,2) */l_uiReturn = SQLSetDescField (l_hDesc,1,SQL_DESC_TYPE,(VOID*)SQL_C_NUMERIC,0);l_uiReturn = SQLSetDescField (l_hDesc,1,SQL_DESC_PRECISION,(VOID*) 5,0);l_uiReturn = SQLSetDescField (l_hDesc,1,SQL_DESC_SCALE,(VOID*) 2,0);
#pragma endregionl_uiReturn = SQLFetch(m_hStatement);if (l_uiReturn != SQL_SUCCESS && l_uiReturn != SQL_SUCCESS_WITH_INFO){return l_oRetval;}SQL_NUMERIC_STRUCT l_tFloat;SQLINTEGER l_siLength = 0;/* 获得相应的浮点数形数据 */SQLGetData(m_hStatement,1,SQL_ARD_TYPE,&l_tFloat,sizeof(l_tFloat),&l_siLength);　　//这里一定要使用SQL_ARD_TYPE,意思是要使用我们上面设置好的数据格式  SQLFreeHandle(SQL_HANDLE_DESC,l_hDesc);SQLFreeHandle(SQL_HANDLE_STMT,m_hStatement);

double GetDoubleFromHexStruct(SQL_NUMERIC_STRUCT & p_rtNumeric)
{long l_lValue =0;int l_iLastVal = 1,l_iCurrentVal = 0;int l_iLsd = 0 ,l_iMsd = 0;for(int i = 0;i < 16 != 0;i++){l_iCurrentVal = (int) p_rtNumeric.val[i];l_iLsd = l_iCurrentVal % 16;l_iMsd = l_iCurrentVal / 16;l_lValue += l_iLastVal * l_iLsd;    l_iLastVal = l_iLastVal * 16;    l_lValue += l_iLastVal * l_iMsd;l_iLastVal = l_iLastVal * 16;    }long l_lDivisor = 1;for (int i =0;i < p_rtNumeric.scale;i++){l_lDivisor = l_lDivisor * 10;}return (double)(l_lValue/(double)l_lDivisor);}