将 SQL 查询转换为 Grails

Question

如何将以下 3 table SQL 查询转换为 Grails？

SELECT t.name, count(*) as c
FROM topic t
LEFT OUTER JOIN article_topics at
ON t.id = at.topic_id
LEFT OUTER JOIN article a
ON at.article_id = a.id
GROUP BY t.name

我一直在尝试类似于但不确定如何进行连接的操作

def criteria = Topic.createCriteria()
    criteria.list {
        groupProperty("name")
        projections {
            count('*')
        }
    }

或者可能是 better/easier 如果我尝试使用

Topic.executeQuery(..insert sql..)

如果有帮助，我有 Article 和 Topic GORM 对象，在 Article

static mapping = {
  topics lazy: false, joinTable: [name: 'article_topics', column: 'topic_id', key: 'article_id']
}

Answer 1

托德。在 grails 中，您可以使用 hibernate 本机 sql 查询，如 hacki 先生 post 中所述。

我分享了一个取自生产代码的示例，该示例使用了出版物中描述的技术并使用了左连接。

List<Map<String, Object>> resumeInMonth(final String monthName) {
    final session = sessionFactory.currentSession
    final String query = """
        SELECT
            t.id AS id,
            e.full_name AS fullName,
            t.subject AS issue,
            CASE t.status
                WHEN 'open' THEN 'open'
                WHEN 'pending' THEN 'In progress'
                WHEN 'closed' THEN 'closed'
            END AS status,
            CASE t.scheduled
                WHEN TRUE THEN 'scheduled'
                WHEN FALSE THEN 'non-scheduled'
            END AS scheduled,
            ifnull(d.name, '') AS device,
            DATE(t.date_created) AS dateCreated,
            DATE(t.last_updated) AS lastUpdated,
            IFNULL(total_tasks, 0) AS tasks
        FROM
            tickets t
                INNER JOIN
            employees e ON t.employee_id = e.id
                LEFT JOIN
            devices d ON d.id = t.device_id
                LEFT JOIN
            (SELECT
                ticket_id, COUNT(1) AS total_tasks
            FROM
                tasks
            GROUP BY ticket_id) ta ON t.id = ta.ticket_id
        WHERE
            MONTHNAME(t.date_created) = :monthName
        ORDER BY dateCreated DESC
    """
    final sqlQuery = session.createSQLQuery(query)
    final results = sqlQuery.with {
        resultTransformer = AliasToEntityMapResultTransformer.INSTANCE

        setString('monthName', monthName)

        list()
    }

    results
}

希望对你有用

将 SQL 查询转换为 Grails

Translating SQL query to Grails

grails

grails-orm