【问题标题】：#1054 - Unknown column 'ord' in 'field list'#1054 - '字段列表'中的未知列'ord'
【发布时间】：2015-05-13 16:20:20
【问题描述】：

我正在使用 mySQL。

当我尝试将参数添加到应该对我的结果进行排序的 SQL 查询中时出现错误：

1054 - '字段列表'中的未知列 'ord'

SELECT tkt.* , ord = 0 
            FROM tkts_follows AS t2f 
            JOIN tkts_topics AS tkt ON (t2f.tktID = tkt.id 
                                    AND t2f.type = 'pin' 
                                    AND t2f.userID = 1 )
            UNION ALL 
            SELECT * , ord = 1 
            FROM tkts_topics AS tkt
            WHERE  (1=1 ) AND NOT EXISTS (SELECT * 
                    FROM tkts_follows AS t2f 
                            WHERE t2f.tktID = tkt.id AND t2f.type = 'pin' AND t2f.userID = 1) 
                            ORDER BY ord, last_update DESC LIMIT 0, 10

【问题讨论】：

选择中的ord = 0 是什么？
我用来对结果进行排序的新参数 - @AbhikChakraborty
“参数”是什么意思

标签： php mysql

【解决方案1】：

看起来你正在设置一些订购号，它需要是

SELECT tkt.* , 0 as ord
FROM tkts_follows AS t2f 
JOIN tkts_topics AS tkt ON t2f.tktID = tkt.id 
AND t2f.type = 'pin'
AND t2f.userID = 1 
UNION ALL 
SELECT * , 1 as ord 
FROM tkts_topics AS tkt
WHERE  1=1  AND NOT EXISTS (
SELECT 1 
FROM tkts_follows AS t2f 
WHERE t2f.tktID = tkt.id AND t2f.type = 'pin' AND t2f.userID = 1
) 
ORDER BY ord, last_update DESC LIMIT 0, 10

【讨论】：

【解决方案2】：

应该是“0 AS ord”或“1 AS ord”。此外，在对 UNION ALL 进行排序时，我建议将所有内容放在子查询中并对结果进行排序，因为对 UNION 进行排序会产生意想不到的结果。

SELECT
    *
FROM (
    SELECT
        tkt.*
        , 0 AS ord
    FROM tkts_follows AS t2f 
        JOIN tkts_topics AS tkt ON t2f.tktID = tkt.id
            AND t2f.type = 'pin'
            AND t2f.userID = 1
    UNION ALL 
    SELECT
        *
        , 1 AS ord
    FROM tkts_topics AS tkt
    WHERE  (1=1)
        AND NOT EXISTS (
            SELECT * 
            FROM tkts_follows AS t2f 
            WHERE t2f.tktID = tkt.id
                AND t2f.type = 'pin'
                AND t2f.userID = 1
        ) 
) AS UNIONS
ORDER BY ord, last_update DESC
LIMIT 0, 10

【讨论】：