SQLite高级语句查询
在SQLite中,进行复杂查询通常涉及到JOIN操作、子查询、聚合函数和窗口函数等。以下是一些示例:
- 使用JOIN连接两个表:
SELECT Orders.orderID, Customers.customerName
FROM Orders
JOIN Customers ON Orders.customerID = Customers.customerID;
- 使用子查询:
SELECT orderID, customerID
FROM Orders
WHERE customerID = (SELECT customerID FROM Customers WHERE customerName = 'Apple');
- 使用聚合函数(如COUNT、SUM、AVG):
SELECT productName, COUNT(*)
FROM OrderDetails
GROUP BY productName;
- 使用窗口函数(如ROW\_NUMBER、RANK、DENSE\_RANK):
SELECT productName, price,
ROW_NUMBER() OVER (ORDER BY price DESC) AS rank
FROM Products;
确保表和字段名称是正确的,并根据实际数据库结构调整查询语句。
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