用三個表連接sql查詢

Question

我必須加入三張桌子。

1 表是交易，下一張表是商店，第 3 表是天氣。

我想從所有這三個中獲取數據，但在天氣表 > id,tamp_c,datetime 列名的情況下。

查詢是：-

 select HOUR(transaction.time) as Hour ,
        TRUNCATE(sum(transaction.total),2) as Total_Sales,
        shops.gstIncludedSales as GST_Inc_Sales,
        shops.gstFreeSales as GST_Free,weather.temp_c 
        from transaction,shops,weather 
        where transaction.shopid=shops.id and transaction.shopid=7
        and transaction.transaction_date ='2015-05-25' 
        group by hour 
        ORDER BY hour DESC

問題是我想對像time(datetime)='2015-05-25'這樣的特定日期應用帶有weather.datetime表分離的where子句，但它不起作用。

Answer 1

嘗試這個：

WHERE transaction.transaction_date >= '2015-05-25' AND transaction.transaction_date < '2015-05-26'

這將在全天（午夜到午夜 - 隱含時間）返回帶有時間戳的行。

如果您有 SQLServer 2014，則可以使用 DATE(transaction.transaction_date)。

Answer 2

這是否做你想做的

SELECT HOUR(transaction.time) as Hour ,
   TRUNCATE(sum(transaction.total),2) as Total_Sales,
   shops.gstIncludedSales as GST_Inc_Sales,
   shops.gstFreeSales as GST_Free,weather.temp_c 
FROM transaction
JOIN shops ON transaction.shopid=shops.id
JOIN weather ON DATE(transaction.transaction_date) = DATE(weather.datetime)
WHERE DATE(transaction.transaction_date)='2015-05-25' AND transaction.shopid=7
GROUP by hour 
ORDER BY hour DESC

（假設您使用的是 MySQL）