正确合并查询SQL

MegaRoks

我有三个表USERS，BOOKMARKS_PRODUCTS，PRODUCTS。

我需要从USERS表中选择一个用户ID，在BOOKMARKS_PRODUCTS表中找到它，从PRODUCTS表中跨表中找到PRODUCTS_ID字段，在BOOKMARKS_PRODUCTS表中找到所有产品PRODUCTS。

SELECT U.USER_NAME, U.USER_EMAIL, U.USER_PHONE, U.USER_AVATAR, U.ABOUT
FROM USERS AS U
WHERE U.USER_ID = '${user_id}'
SELECT B.PRODUCT_ID
FROM BOOKMARKS_PRODUCTS AS B
WHERE B.USER_ID = '${user_id}'
SELECT P.*
FROM PRODUCTS AS P
WHERE P.PRODUCT_ID = '${product_id}'

请帮助我正确执行此操作。

百年

您可以在查询中使用JOIN从不同的表中获取数据。

SELECT U.USER_NAME, U.USER_EMAIL, U.USER_PHONE, U.USER_AVATAR, U.ABOUT, B.PRODUCT_ID, P.* 
FROM USERS AS  U 
INNER JOIN BOOKMARKS_PRODUCTS AS B ON B.USER_ID = U.USER_ID -- OR '${user_id}'
INNER JOIN PRODUCTS AS P ON P.PRODUCT_ID = B.PRODUCT_ID -- OR '${product_id}'
WHERE U.USER_ID = '${user_id}'

欲了解更多信息，请参阅

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