Question

SELECT name,trans FROM skyplan_deploy.deploy_stars d WHERE d.apt='KOPF' AND d.name!=d.trans  

LEFT OUTER JOIN  

(SELECT distinct c.star_ident,c.fix_ident from corept.std_star_leg c  
    INNER JOIN  
    (SELECT star_ident,transition_ident,max(sequence_num) seq,route_type  
     FROM corept.std_star_leg  
     WHERE data_supplier='J' AND airport_ident='KOPF'  
     group by star_ident,transition_ident)b  
    ON c.sequence_num=b.seq and c.star_ident=b.star_ident and   c.transition_ident=b.transition_ident) as y  
ON c.sid_ident=x.name AND c.fix_ident=x.trans  
where y.data_supplier='J' and y.airport_ident='KOPF' and y.name is null;

执行上述查询时，我收到以下语法错误。

您的SQL语法有错误;检查手册   对应于您的MySQL服务器版本，以便使用正确的语法   靠近'LEFT OUTER JOIN

（从corept.std_sta'中选择不同的c.star_ident，c.fix_ident   3

我使用了左连接，这样我就能从上面的两个查询中获得数据差异。我甚至将where条件放在最后。

Answer 1

找到错误的一个好方法是将其分解并分别尝试组件。例如，尝试：

SELECT star_ident,transition_ident,max(sequence_num) seq,route_type  
FROM corept.std_star_leg  
WHERE data_supplier='J' AND airport_ident='KOPF'  
group by star_ident,transition_ident

查看该子查询是否存在任何问题。

当查询没有语法错误但没有产生预期结果时，将查询分解为可理解的部分通常是调试它的最快方法。

Answer 2

您的错误原因是无效使用LEFT JOIN。基本SELECT语法如下，

SELECT ...
FROM ... JOIN...
WHERE ...
GROUP BY...
ORDER BY ...

您在LEFT JOIN子句之后使用WHERE会导致语法错误。

请解决错误

2 个答案: