php - 连接两个查询以形成结果集

Question

大家好，我必须连接两个查询才能形成结果集:-

第一:

SELECT  
    orderId,
    GROUP_CONCAT(DISTINCT(categoryId) ORDER BY orderId SEPARATOR ', ') as catId 
FROM 
    ecart_product 
INNER JOIN ecart_orderdetail 
WHERE 
    ecart_orderdetail.productId = ecart_product.id 
group by orderId

这给了我

orderId catId167 59, 2168 2169 2170 2171 2172 48, 2173 2174 2

2nd:

select * from ecart_orders

在这两个 orderId 中都很常见，这怎么可能是 join ？

Answer 1

假设orderId是ecart_orders表中的PK，并且它有productId列。
你可以试试这个:

SELECT  
    orderId,
    GROUP_CONCAT(DISTINCT(categoryId) ORDER BY orderId SEPARATOR ', ') as catId ,
    ecart_orders.*
FROM 
    ecart_product 
INNER JOIN ecart_orderdetail 
    ON ecart_orderdetail.productId = ecart_product.id 
INNER JOIN ecart_orders
    ON ecart_orders.productId = ecart_product.id    
group by orderId