我必须运行1个查询，然后运行第一个查询的结果。我意识到我可能只是将第一个结果集抛出一个数组然后遍历数组，但有没有办法只是嵌套查询，这样我就不必乱七八糟了？
这是我目前的代码：
SqlConnection conn2 = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["wesdb1SQL"].ToString());
SqlCommand strSQL2;
SqlDataReader itemReader2;
using (SqlConnection conn = new SqlConnection(System.Configuration.ConfigurationManager.ConnectionStrings["wesdb1SQL"].ToString()))
using (SqlCommand strSQL = conn.CreateCommand())
{
strSQL.CommandText = "SELECT item_id,item_lot,item_title,item_est_lo,item_est_hi,item_timed_start,item_reserve FROM tblItem WHERE (item_sale_id=@item_sale_id) ORDER BY item_lot";
strSQL.Parameters.Add(new SqlParameter("@item_sale_id", SqlDbType.VarChar, 10, ParameterDirection.Input, true, 0, 0, "item_sale_id", DataRowVersion.Current, itemSaleId1_Var));
try
{
conn.Open();
using (SqlDataReader itemReader = strSQL.ExecuteReader())
{
if (itemReader.Read())
{
using (conn2)
using (strSQL2 = conn2.CreateCommand())
{
strSQL2.CommandText = "SELECT TOP (1) MAX(tblBidHistory.bid_price) AS bid_price, tblMailList.mail_Email1, tblBidHistory.bid_bidder_id, tblMailList.mail_FirstName, tblMailList.mail_LastName, tblBidHistory.bid_item_id FROM tblBidHistory INNER JOIN tblBidder ON tblBidHistory.bid_bidder_id = tblBidder.bidder_number AND (tblBidder.bidder_sale_id=@item_sale_id) INNER JOIN tblMailList ON tblBidder.bidder_mail_id = tblMailList.mail_ID GROUP BY tblMailList.mail_Email1, tblBidHistory.bid_bidder_id, tblMailList.mail_FirstName, tblMailList.mail_LastName, tblBidHistory.bid_item_id,tblBidHistory.bid_type,tblBidHistory.bid_date HAVING (tblBidHistory.bid_item_id=@item_id) AND (tblBidHistory.bid_type = '2') ORDER BY bid_price DESC,bid_date DESC";
strSQL2.Parameters.Add(new SqlParameter("@item_sale_id", SqlDbType.VarChar, 10, ParameterDirection.Input, true, 0, 0, "item_sale_id", DataRowVersion.Current, itemSaleId1_Var));
strSQL2.Parameters.Add(new SqlParameter("@item_id", SqlDbType.VarChar, 10, ParameterDirection.Input, true, 0, 0, "item_id", DataRowVersion.Current, itemReader["item_id"].ToString()));
try
{
conn2.Open();
using (itemReader2 = strSQL2.ExecuteReader())
{
if (itemReader2.Read())
{
if (count % 2 == 0)
{
results_Var += "<tr><td colspan=\"2\"><font size=\"2\">" + itemReader["item_lot"].ToString() + " - <u>" + itemReader["item_title"].ToString() + "</u></font></td><td><font size=\"2\">$" + itemReader["item_est_lo"].ToString() + " - $" + itemReader["item_est_hi"].ToString() + "</font></td><td>" + itemReader2["bid_price"].ToString() + " - " + itemReader2["bid_bidder_id"].ToString() + " (" + itemReader2["mail_FirstName"].ToString() + " " + itemReader2["mail_LastName"].ToString() + ")</td><td><font size=\"2\">$" + itemReader2["bid_price"].ToString() + "</font></td></tr>";
}
else
{
results_Var += "<tr><td colspan=\"2\" bgcolor=\"#b0e0e6\"><font size=\"2\">" + itemReader["item_lot"].ToString() + " - <u>" + itemReader["item_title"].ToString() + "</u></font></td><td><font size=\"2\">$" + itemReader["item_est_lo"].ToString() + " - $" + itemReader["item_est_hi"].ToString() + "</font></td><td>" + itemReader2["bid_price"].ToString() + " - " + itemReader2["bid_bidder_id"].ToString() + " (" + itemReader2["mail_FirstName"].ToString() + " " + itemReader2["mail_LastName"].ToString() + ")</td><td><font size=\"2\">$" + itemReader2["bid_price"].ToString() + "</font></td></tr>";
}
}
itemReader2.Close();
}
}
catch (Exception e1)
{
throw new Exception(e1.Message);
}
finally
{
conn2.Close();
}
}
}
itemReader.Close();
}
}
catch (Exception e2)
{
throw new Exception(e2.Message);
}
finally
{
conn.Close();
}
}
两个查询的输出用于创建多行数据的表。每行是数据库中的一个项目，其中出价者的信息最高，包括出价本身以及一些类别信息。类别信息是第一个查询，唯一项目信息是第二个查询（您可以在其中查看使用两个结果集构建的表行）。
修改
我稍微更改了xQbert查询，结果是：
SELECT MAX(BH.bid_price) AS bid_price, ML.mail_Email1, BH.bid_bidder_id, ML.mail_FirstName, ML.mail_LastName, BH.bid_item_id, I.item_lot, I.item_title, I.item_est_lo, I.item_est_hi, I.item_timed_start, I.item_reserve
FROM tblBidHistory BH
INNER JOIN tblBidder B ON BH.bid_bidder_id = B.bidder_number AND (B.bidder_sale_id=@item_sale_id)
INNER JOIN tblMailList ML ON B.bidder_mail_id = ML.mail_ID
INNER JOIN tblItem I ON I.Item_ID = BH.Bid_item_id
WHERE (I.item_sale_id=@item_sale_id) And (BH.bid_type = '2')
GROUP BY ML.mail_Email1, BH.bid_bidder_id, ML.mail_FirstName, ML.mail_LastName, BH.bid_item_id, BH.bid_type, BH.bid_date, I.item_lot, I.item_title, I.item_est_lo, I.item_est_hi, I.item_timed_start, I.item_reserve
ORDER BY I.Item_Lot
这为我提供了数据，但它为每个项目提供了每个项目的出价者，而不是每个项目的最高出价者。我不确定是否需要进行不同的分组，或者可能使用子查询。
另外，要做到这一点，我只是进行1次查询。但是，我仍然想知道如何在SQL中创建嵌套查询。
答案 0 :(得分：2)
尝试：
select * from
(SELECT i.item_id,
i.item_lot,
i.item_title,
i.item_est_lo,
i.item_est_hi,
i.item_timed_start,
i.item_reserve,
h.bid_price,
l.mail_Email1,
h.bid_bidder_id,
l.mail_FirstName,
l.mail_LastName,
h.bid_item_id,
row_number() over (partition by i.item_id
order by h.bid_price DESC, h.bid_date DESC) rn
FROM tblItem i
INNER JOIN tblBidHistory h
on i.item_id = h.bid_item_id=i.item_id AND h.bid_type = '2'
INNER JOIN tblBidder b
ON h.bid_bidder_id = b.bidder_number AND b.bidder_sale_id=i.item_sale_id
INNER JOIN tblMailList l
ON b.bidder_mail_id = l.mail_ID
WHERE i.item_sale_id=@item_sale_id) v
where rn=1
答案 1 :(得分：1)
我非常怀疑以下是正确的：太多的假设和对问题缺乏理解：但这是加入他们的一种方式 假设商品通过Bid_Item_ID加入BH 为I.Item_lot添加了顺序并添加了项目数据 添加项目数据以进行选择和分组。
SELECT TOP (1) MAX(BH.bid_price) AS bid_price, ML.mail_Email1, BH.bid_bidder_id,
ML.mail_FirstName, ML.mail_LastName, BH.bid_item_id, I.item_lot, I.item_title,
I.item_est_lo, I.item_est_hi, I.item_timed_start, I.item_reserve
FROM tblBidHistory BH
INNER JOIN tblBidder B
ON BH.bid_bidder_id = B.bidder_number
AND (B.bidder_sale_id=@item_sale_id)
INNER JOIN tblMailList ML
ON B.bidder_mail_id = ML.mail_ID
INNER JOIN tblItem I
ON I.Item_ID = BH.Bid_item_id
WHERE (I.item_sale_id=@item_sale_id)
GROUP BY ML.mail_Email1, BH.bid_bidder_id,
ML.mail_FirstName, ML.mail_LastName, BH.bid_item_id, BH.bid_type, BH.bid_date,
I.item_lot, I.item_title, I.item_est_lo, I.item_est_hi, I.item_timed_start,
I.item_reserve
HAVING (BH.bid_item_id=@item_id) AND (BH.bid_type = '2')
ORDER BY I.Item_Lot, BH.bid_price DESC, BH.bid_date DESC