Question

我试图多次在同一张桌子上进行自我左联接。每当我执行此查询时，我都会遇到异常。

类org.hibernate.hql.internal.ast.QuerySyntaxException 消息意外令牌：LEFT靠近第13行，第33列

Query query = null
        def hql = $/
                SELECT
                    c1.id,
                    c1.parentId,
                    c1.navDepth,
                    c1.navOrder,
                    c1.title,
                    c1.fileName,
                    // aliasing filenamepath column as filepath.
                    REPLACE(c1.fileNamePath, 'home/', '') AS filepath
                FROM Content AS c1

                WHERE 0 = 0
                LEFT JOIN Content AS c2
                ON c1.col1 = c2.fileNameLookup
                AND c1.col1 = c2.col1

                LEFT JOIN Content AS c3
                ON c1.col2 = c3.fileNameLookup
                AND c1.col2 = c3.col2

                LEFT JOIN Content AS c4
                ON c1.col3 = c4.fileNameLookup
                AND c1.col3 = c4.col3

                LEFT JOIN Content AS c5
                ON c1.col4 = c5.fileNameLookup
                AND c1.col4 = c5.col4

                LEFT JOIN Content AS c6
                ON c1.col5 = c6.fileNameLookup
                AND c1.col5 = c6.col5

                LEFT JOIN Content AS c7
                ON c1.col6 = c7.fileNameLookup
                AND c1.col6 = c7.col6

                LEFT JOIN Content AS c8
                ON c1.col7 = c8.fileNameLookup
                AND c1.col7 = c8.col7

                LEFT JOIN Content AS c9
                ON c1.col8 = c9.fileNameLookup
                AND c1.col8 = c9.col8

                LEFT JOIN Content AS c10
                ON c1.col9 = c10.fileNameLookup
                AND c1.col9 = c10.col9

                AND c1.isNavItem = 1
                GROUP BY c1.id
                ORDER BY c1.navDepth, c1.navOrder
                /$
                //def result = Content.executeQuery(hql)
        query = Content.executeQuery(hql).setResultTransformer(AliasToEntityMapResultTransformer.INSTANCE)
                .addScalar("filepath", new StringType())
        List<Map<String,Object>> result = query.list()
        return result

任何人都可以让我知道我做错了什么，我怎样才能让它发挥作用？

Answer 1

WHERE错位：

FROM 
WHERE 0 = 0
LEFT JOIN Content AS c2

应该是：

FROM
LEFT JOIN
LEFT JOIN
...
WHERE
GROUP BY
ORDER BY

在查询中没有设置 filepath 参数，如果它必须在WHERE子句中而不在SELECT子句中：
```
addScalar("filepath", new StringType())
```
您使用LEFT JOINS和ON子句编写了一个SQL查询，但这是本机SQL查询语法。在HQL中，您加入了可导航的实体关联，并且没有HQL ON子句。

要模拟ON子句，您需要使用the with directive：
```
from Cat as cat
    left join cat.kittens as kitten
        with kitten.bodyWeight > 10.0
```
首先尝试不使用变压器。只需执行查询并让它首先返回List。如果可行，那么尝试使用变压器。如果不是，您的查询语法仍然存在问题。

做自我左连接时意外离开

1 个答案: