選擇內部聯接SQL語句中的特定列

Question

我想從我上一個內部聯接的“ Products選擇特定的列（“ Name ）。 我怎樣才能做到這一點？

這是我的SQL語句：

SqlCommand cmd = new SqlCommand("SELECT * FROM CustomerDetails cd INNER JOIN CustomerProducts cp ON cp.CustomerID = cd.Id INNER JOIN Products p ON cp.ProductID = p.ProductID", conn);

到目前為止，我已經明白了，是否可以為此提供一欄？ 像Name一樣，因為它們具有相同的ID，所以含有二氧化碳，工業氧氣？ 謝謝

Answer 1

SqlCommand cmd = new SqlCommand("select p.[name], cd.* FROM CustomerDetails cd Inner Join CustomerProducts cp ON cp.CustomerID = cd.Id Inner Join Products p ON cp.ProductID = p.ProductID", conn);

編輯：我同意下面的評論，不建議使用cd。*，它應該是cd.Id，cd.CustomerName ...等。

這應該使您將名稱歸為一列：

;WITH Customers AS
(
    select cd.Id, cd.customer ... FROM CustomerDetails cd 
)

SELECT stuff(
(
    select ', ' + p.[name] FROM Customers cd Inner Join CustomerProducts cp ON cp.CustomerID = cd.Id Inner Join Products p ON cp.ProductID = p.ProductID
    FOR XML PATH('')
), 1, 2, '')
, c.Id, c.CustomerName ...
FROM Customers c

Answer 2

select p.Name, cd.ColumnA, cd.ColumnB, cd.ColumnC
FROM CustomerDetails cd 
Inner Join CustomerProducts cp ON cp.CustomerID = cd.Id 
Inner Join Products p ON cp.ProductID = p.ProductID