Sql select inner join and union 3 表

Question

我一直在尝试合并三个并加入一个 table，我成功地选择了仅使用内部联接并且还结合了内部联接和联合，但我的问题是获得回复 ID 我已经尝试了很多显示回复 ID 但在其他工作正常时不断出错的事情

下面sql给我这个

     //$dsnnot->prepare("SELECT * FROM replys r INNER JOIN blog_post b ON r.rid = b.BID WHERE b.UserName = :ownerna AND r.read = 1");        
        
        $dsnnot->prepare('SELECT * FROM (
            SELECT "post" AS type, BID AS eid, blog_title AS title, Time AS stime, blog_body AS description, UserName AS owner FROM blog_post b 
INNER JOIN replys r ON r.rid = b.BID WHERE b.action = "active" AND r.read = 1
            UNION 
            SELECT "jaile" AS , jid AS eid, orgname AS title, jaildate AS stime, OrgDescription AS description, jailorgnowner AS owner FROM jailorgname
            UNION
            SELECT "articl" AS type, TID AS eid, Atitle AS title, Atime AS stime, Abody AS description, Auser AS owner FROM articlespost
            
        ) foo  WHERE owner = :ownerna');

我是这样输出的

type > Show where it came from

eid > Show main post id's

title > Show post title

owner > Show post author

stime > Show time

description > Show post content

现在我的问题是显示 replys > RID，我也想把它放在我的 php

Answer 1

您必须具有相同数量的列，并且每个 SELECT 中的列必须具有相同的数据类型和相同的顺序。因此，如果您想要回复 ID，则必须为每个 select 添加一个空值，而不是 select。

$dsnnot->prepare('
SELECT *
FROM (
  SELECT
    "post" AS type,
    BID AS eid,
    blog_title AS title,
    Time AS stime,
    blog_body AS description,
    UserName AS owner,
    r.replyID
  FROM blog_post b
  INNER JOIN replys r ON r.rid = b.BID
  WHERE b.action = "active" AND r.read = 1

  UNION

  SELECT
    "jaile" AS type,
    jid AS eid,
    orgname AS title,
    jaildate AS stime,
    OrgDescription AS description,
    jailorgnowner AS owner,
    null AS replyID
  FROM jailorgname

  UNION

  SELECT
    "articl" AS type,
    TID AS eid,
    Atitle AS title,
    Atime AS stime,
    Abody AS description,
    Auser AS owner,
    null AS replyID
  FROM articlespost
) foo
WHERE owner = :ownerna');

Sql select inner join and union 3 表

Sql select inner joine and union 3 tables

php

mysql

sql-server

union

join