mysql联合查询，每个联合上都有单独的别名

Question

正在创建一个搜索查询mysql，使用UNION连接多个表，现在我的问题是添加别名来标识每个表，因为如果我添加带别名的表名，它将显示错误COLUMN NOT FOUND 我试图在每个联合表上添加别名，但收到错误，我不知道该怎么做才能写入它，任何人都可以帮忙。

查询

SELECT * FROM (
    (
        SELECT 'food' as type,
        food_id AS item_id,
        food_name AS item_name,
        primary_image AS item_img,
        food_price AS item_price,
        food_currency AS item_currency,
        food_discount AS item_discount,
        chef_status AS ison
        FROM foods
    ) AS f

    UNION

    (
        SELECT 'chef' as type,
        chef_pagename AS item_id,
        business_name AS item_name,
        chef_photo AS item_img,
        NULL AS item_price,
        NULL AS item_currency,
        NULL AS item_discount,
        chef_status AS ison
        FROM our_chefs
    ) AS c
) AS fsc

WHERE f.food_name LIKE '%chicken%'
OR f.item_price LIKE '%100%'
OR c.business_name LIKE '%chicken%'
AND fsc.ison = 1

谢谢大家的贡献，我现在通过这样做解决了问题

WHERE item_name LIKE '%chicken%'
OR item_price LIKE '%100%'
AND fsc.ison = 1

Answer 1

我想这就是你想要的:

SELECT * FROM (

  (
    SELECT 'food' as type,
    food_id AS item_id,
    food_name AS item_name,
    primary_image AS item_img,
    food_price AS item_price,
    food_currency AS item_currency,
    food_discount AS item_discount,
    chef_status AS ison
    FROM foods
    WHERE food_name LIKE '%chicken%'
    OR item_price LIKE '%100%'
  )  

  UNION

  (
    SELECT 'chef' as type,
    chef_pagename AS item_id,
    business_name AS item_name,
    chef_photo AS item_img,
    NULL AS item_price,
    NULL AS item_currency,
    NULL AS item_discount,
    chef_status AS ison
    FROM our_chefs
    WHERE business_name LIKE '%chicken%'
  )  
) AS a

WHERE  a.ison = 1