Question

我需要使用总共四（4）个表。基本上一个从另一个拉取来从另一个拉取数据以获取前一个表数据等等。

我无法在没有超时的情况下成功运行查询。我想在SUM VISITS

中显示商品的ORDER MONTH以及特定时间段内的总销售额

表结构

table1 (WebVisits)
ID   DATE        WEBNUMBER  VISITS
1    2012-01-01  apw-rtr8   2
..   ...         ...        ..


table2 (Commodities)
ID      WEBNUMBER   TIER1
5791    apw-rtr8    Refrigeration
..      ...         ...


table3 (Attributes)
ITEM        WEB_NUM
APW-RTR-8   apw-rtr8
..          ...


table4 (SalesData)
ID     ITEM        QUANTITY  UNIT_PRICE  TRANS_DATE
31905  APW-RTR-8   1         1522.38     2012-02-05
..     ...         ...       ...         ...

SELECT 
    MONTH(t1.DATE) AS MONTH, 
    SUM(t1.VISITS) as Visits,
    t2.TIER1 as Category
FROM
    table1 t1
        LEFT JOIN
    table2 t2 ON t1.WEBNUMBER = t2.WEBNUMBER
        LEFT JOIN
    table3 t3 ON t2.WEBNUMBER = t3.WEB_NUM
WHERE
    t1.DATE BETWEEN '2012-01-01' AND '2012-05-31'
        AND t3.TIER1 = 'Cooking Equipment '
        AND EXISTS( SELECT 
            sum(t4.UNIT_PRICE * t4.QUANTITY) as total
        FROM
            table4 t4
        WHERE
            t4.ITEM = t3.ITEM
                AND t4.TRANS_DATE BETWEEN '2012-01-01' AND '2012-05-31')
GROUP BY MONTH
ORDER BY MONTH

基本上，类别（TIER1）将是已知的，日期范围将是已知的。我希望它在上面的查询中吐出与此类似的结果：

MONTH   Visits  Total     Category
1       4054    32058.08  Cooking Equipment 
2       3564    28116.17  Cooking Equipment 
3       4514    25819.66  Cooking Equipment 
4       3621    18732.96  Cooking Equipment 
5       6521    55378.11  Cooking Equipment

Answer 1

我开始编写查询并意识到我写的几乎和你写的一样。

确保存在以下indexes：

table1.DATE
table1.WEBNUMBER
table2.WEBNUMBER
table3.WEB_NUM
table4.ITEM
table4.TRANS_DATE

编辑：

试试这个：

SELECT 
    MONTH(table1.DATE) AS MONTH, 
    SUM(table1.VISITS) as Visits, 
    table2.TIER1 as Category, 
    SUM(table4.UNIT_PRICE * table4.QUANTITY) 
FROM table1 
LEFT JOIN table2 USING(WEBNUMBER) 
LEFT JOIN table3 table1.WEBNUMBER = table3.WEB_NUM 
LEFT JOIN table4 table1.WEBNUMBER = table4.ITEM 
WHERE table2.TIER1 = 'Cooking Equipment' 
AND table4.TRANS_DATE BETWEEN '2012-01-01' 
AND '2012-05-31' 
GROUP BY MONTH 
ORDER BY MONTH

MySQL查询使用4个表，LEFT JOIN和WHERE EXISTS

1 个答案: