我有四个表,我想使用SQL查询加入它们并在产品页面上显示产品
Table 1 [table name: A] has product_id and category_id,
Table 2 [table name: B] has product_id, and our_price,
Table 3 [table name: C] has product_id, and product_name
Table 4 [table name: D] has product_id, description, and saving_price.
在这里,我想
join Table A, B, C, and D
和SELECT all product's
数据from tables B, C, D which category_id = 77 in table A
。
我想在产品页面上打印product_name, description, saving_price, and our_price
,其类别ID为77.
答案 0 :(得分:0)
大概这就是你想要的,虽然很难从你问的方式知道
SELECT
A.product_id,
A.category_id,
B.our_price,
C.product_name,
D.description,
D.saving_price
FROM
A
INNER JOIN B ON A.product_id = B.product_id
INNER JOIN C ON A.product_id = C.product_id
INNER JOIN D ON A.product_id = D.product_id
WHERE
A.category_id = 77
以上假设所有表中都存在数据。如果您在某些数据中缺少数据,则可能需要使用LEFT OUTER JOIN