Question

我似乎无法获得以下查询的结果，以下查询返回NULL

查询联盟

"SELECT isbn    

    FROM ".TBL_BOOKS." 

    WHERE rank < 200000 AND rank IS NOT NULL 
    AND lowest_new_price < amazon_new_price/100*80 
    AND amazon_new_price < 9999 
    AND ROUND((amazon_new_price/100*80) - lowest_new_price) > (lowest_new_price/100*".MARGIN.") 

UNION 

SELECT isbn 

    FROM ".TBL_BOOKS." 

    WHERE rank < 200000 AND rank IS NOT NULL 
    AND lowest_used_price < amazon_used_price/100*80 
    AND amazon_used_price < 9999 
    AND amazon_used_price < amazon_new_price 
    AND ROUND((amazon_used_price/100*80) - lowest_used_price) > (lowest_used_price/100*".MARGIN.") 

ORDER BY rank ASC";

但这两个quires在他们自己的工作正常

查询1

"SELECT isbn    

    FROM ".TBL_BOOKS." 

    WHERE rank < 200000 AND rank IS NOT NULL 
    AND lowest_new_price < amazon_new_price/100*80 
    AND amazon_new_price < 9999 
    AND ROUND((amazon_new_price/100*80) - lowest_new_price) > (lowest_new_price/100*".MARGIN.") 
ORDER BY rank ASC";

查询2

"   SELECT isbn 

        FROM ".TBL_BOOKS." 

        WHERE rank < 200000 AND rank IS NOT NULL 
        AND lowest_used_price < amazon_used_price/100*80 
        AND amazon_used_price < 9999 
        AND amazon_used_price < amazon_new_price 
        AND ROUND((amazon_used_price/100*80) - lowest_used_price) > (lowest_used_price/100*".MARGIN.") 

ORDER BY rank ASC";

如果我分解了联盟并单独运行了两个查询我就没有问题，但由于某些原因UNION查询不起作用，可能是什么问题？感谢

Answer 1

我认为 - 当您在联合中使用'order by'子句时 - 'order by'参数必须是各个查询返回的字段之一。

mysql有UNION查询问题

1 个答案: