怎样提高数据查询速度

[confideman2000]

我在数据查询中想实现以下功能：
查找一定时间内的所有数据，求每段时间内的平均值，这样连续求出180个平均值
(时间定为1分钟，那么就求出1*180=3个小时的平均值)
我通过 Select avg(var1) from table between starttime1 and endtime1 UNION
Select avg(var1) from table between starttime2 and endtime2 UNION
........................
Select avg(var1) from table between starttime180 and endtime180
来实现，但是运行程序时发现查询速度很慢（2－3秒）尤其当数据记录很多时更慢，
怎样提高数据查询速度.

[y_cc]

算法， 数据结构

[confideman2000]

把时间作为索引还是很慢,Slowly.....................

[taianmonkey]

转载：

怎么用VC来调用存储过程

#include "stdafx.h"
#import "C:\PROGRA~1\COMMON~1\System\ado\msado15.dll" rename( "EOF", "adoEOF" )
struct InitOle
{
InitOle() { ::CoInitialize(NULL); }
~InitOle() { ::CoUninitialize(); }
} _init_InitOle_;
void PrintProviderError(ADODB::_ConnectionPtr pConnection);

int main(int argc, char* argv[])
{
printf("Create a adParamReturnValue for Command object to get return value of stored procedure\n");
printf("Reference :MSDN---Append and CreateParameter Methods Example (VC++)\n");
ADODB::_ConnectionPtr Conn1;
ADODB::_CommandPtr Cmd1;
ADODB::_RecordsetPtr Rs1;
ADODB::_ParameterPtr retParam= NULL;
ADODB::_ParameterPtr inParam=NULL;
ADODB::_ParameterPtr outParam=NULL;
_variant_t vtEmpty (DISP_E_PARAMNOTFOUND, VT_ERROR);
_variant_t vtEmpty2 (DISP_E_PARAMNOTFOUND, VT_ERROR);
_bstr_t bstrConnect( L"driver={sql server};server=Cell;Database=zhg;UID=sa;PWD=;" );
// the following stored procedure return 12345 int value
_bstr_t bstrCreate ( L"create proc sp_AdoTest( @OutParam int OUTPUT,@InParam int ) "
L"as "
L"select @OutParam = @InParam + 10 "
L"select * from Table1"
L"return 12345" );
_bstr_t bstrSP(L"sp_Adotest" );
try
{
_bstr_t bstrEmpty;
Conn1.CreateInstance( __uuidof( ADODB::Connection ) );
Cmd1.CreateInstance( __uuidof( ADODB::Command ) );
Rs1.CreateInstance(__uuidof(ADODB::Recordset));
// Establish connection.
Conn1->ConnectionString = bstrConnect;
Conn1->Open( bstrConnect, bstrEmpty, bstrEmpty, -1 );
// Open recordset.
Cmd1->ActiveConnection = Conn1;
Cmd1->CommandText = bstrSP;
Cmd1->CommandType = ADODB::adCmdStoredProc;
retParam=Cmd1->CreateParameter(_bstr_t("Return"),ADODB::adInteger,ADODB::adParamReturnValue,sizeof(int));
Cmd1->Parameters->Append(retParam);
outParam = Cmd1->CreateParameter(_bstr_t("OutParam"),ADODB::adInteger,ADODB::adParamOutput,sizeof(int));
Cmd1->Parameters->Append(outParam);
inParam = Cmd1->CreateParameter(_bstr_t("InParam"),ADODB::adInteger,ADODB::adParamInput,sizeof(int),_variant_t( (long) 10 ));
inParam->Value=_variant_t( (long) 10 );
Cmd1->Parameters->Append(inParam);
Cmd1->Parameters->Refresh();
Cmd1->Parameters->Item[ _variant_t( _bstr_t("@InParam") ) ]->Value =_variant_t( (long) 11 );
Rs1->put_CursorLocation(ADODB::adUseClient);
Rs1->Open((_variant_t((IDispatch *) Cmd1)),vtEmpty,ADODB::adOpenStatic,
ADODB::adLockReadOnly, -1);
// Get return value of the stored procedure.adCmdUnknown
TCHAR tcbuf[1024];
long retvalue=Cmd1->Parameters->Item[(short)0]->Value;
long p2=Cmd1->Parameters->Item[(short)1]->Value;
long p3=Cmd1->Parameters->Item[(short)2]->Value;
int recordcount=0;
if(Rs1->State==ADODB::adStateClosed)
MessageBox(NULL,"no recordset is returned from the stored procedure","Information",MB_OK);
else
recordcount = Rs1->GetRecordCount();
wsprintf(tcbuf,"retvalue of the stored procedure:%d,input value:%d,output value:%d,record count :%d",
retvalue,p2,p3,recordcount);
MessageBox(NULL,tcbuf,"Output",MB_OK);
}
catch(_com_error &e)
{
_bstr_t bstrSource(e.Source());
_bstr_t bstrDescription(e.Description());
printf("\nCOM error occurred, Source : %s \n Description : %s \n",(LPCSTR)bstrSource,(LPCSTR)bstrDescription);
PrintProviderError(Conn1);
}
return 0;
}
VOID PrintProviderError(ADODB::_ConnectionPtr pConnection)
{
// Print Provider Errors from Connection object.
// pErr is a record object in the Connection's Error collection.
ADODB::ErrorPtr pErr = NULL;
long nCount = 0;
long i = 0;

if( (pConnection->Errors->Count) > 0)
{
nCount = pConnection->Errors->Count;
// Collection ranges from 0 to nCount -1.
for(i = 0; i < nCount; i++)
{
pErr = pConnection->Errors->GetItem(i);
printf("\n\t Error number: %x\t%s", pErr->Number, (LPCSTR)pErr->Description);
}
}
}

[jerry]

建索引

使用存储过程

[confideman2000]

具体怎样实现，多谢

[rockersz]

建立索引的方法很多，要根据表结构来分析，一下子说不清，最好找书看

[artmouse]

你的表结构怎么样的啊，应该有格字段是时间吧，把它作为索引就可以了