【发布时间】：2020-09-25 02:26:09
【问题描述】：
我正在尝试将以下 PostgreSQL 查询转换为 jOOQ，但似乎无法找到解决此问题的适当方法。这是查询：
SELECT b.book_id AS b_id, b.title, b.price, b.amount, b.is_deleted,
to_json(array_agg(DISTINCT aut.*)) as authors,
to_json(array_agg(DISTINCT cat.*)) as categories
FROM book b
LEFT JOIN author_book AS ab ON b.book_id = ab.book_id
LEFT JOIN author AS aut ON ab.author_id = aut.author_id
LEFT JOIN category_book AS cb ON b.book_id = cb.book_id
LEFT JOIN category AS cat ON cb.category_id = cat.category_id
GROUP BY b_id ORDER BY b_id ASC;
到目前为止，这是我在 jOOQ 中想到的：
dslContext
.select(BOOK.BOOK_ID, BOOK.TITLE, BOOK.PRICE, BOOK.AMOUNT, BOOK.IS_DELETED,
DSL.val(DSL.jsonArray(DSL.arrayAggDistinct(AUTHOR.AUTHOR_ID),
DSL.arrayAggDistinct(AUTHOR.FIRST_NAME),
DSL.arrayAggDistinct(AUTHOR.LAST_NAME))
).cast(SQLDataType.JSON),
DSL.val(DSL.jsonArray(DSL.arrayAggDistinct(CATEGORY.CATEGORY_ID),
DSL.arrayAggDistinct(CATEGORY.NAME),
DSL.arrayAggDistinct(CATEGORY.IS_DELETED))
).cast(SQLDataType.JSON)
).from(BOOK
.leftJoin(AUTHOR_BOOK).on(BOOK.BOOK_ID.eq(AUTHOR_BOOK.BOOK_ID))
.leftJoin(AUTHOR).on(AUTHOR_BOOK.AUTHOR_ID.eq(AUTHOR.AUTHOR_ID))
.leftJoin(CATEGORY_BOOK).on(BOOK.BOOK_ID.eq(CATEGORY_BOOK.BOOK_ID))
.leftJoin(CATEGORY).on(CATEGORY_BOOK.CATEGORY_ID.eq(CATEGORY.CATEGORY_ID))
).where(AUTHOR.AUTHOR_ID.eq(Long.valueOf(authorId))
).groupBy(BOOK.BOOK_ID).orderBy(BOOK.BOOK_ID.asc())
当我执行 jOOQ 代码时，出现以下异常：
方言 DEFAULT 不支持类型类 org.jooq.impl.JSONArray
我用谷歌搜索了这个异常，在this 问题中只发现了这个类似的异常。是否有任何适当的解决方法来解决 PostgreSQL to_json 函数的转换以及在给定 aut(hor)/cat(egory) 表的所有字段上保存 DISTINCT 的 array_agg() 组合？
更新： 这是我用来在 jOOQ 中以非类型安全的方式编写查询的另一种方式：
dslContext.resultQuery(DBQueries.GET_ALL_BOOKS_BY_AUTHOR_ID, Long.valueOf(authorId)));
...这里是DBQueries.GET_ALL_BOOKS_BY_AUTHOR_ID 变量的代码：
public class DBQueries {
//...
static String GET_ALL_BOOKS_BY_AUTHOR_ID = "SELECT b.book_id AS b_id, b.title, b.price, b.amount, b.is_deleted, " +
"to_json(array_agg(DISTINCT aut.*)) as authors, to_json(array_agg(DISTINCT cat.*)) as categories " +
"FROM book b " +
"LEFT JOIN author_book AS ab ON b.book_id = ab.book_id " +
"LEFT JOIN author AS aut ON ab.author_id = aut.author_id " +
"LEFT JOIN category_book AS cb ON b.book_id = cb.book_id " +
"LEFT JOIN category AS cat ON cb.category_id = cat.category_id " +
"WHERE aut.author_id = :id " +
"GROUP BY b_id ORDER BY b_id ASC;";
}
顺便说一句，我已经更新了我的问题，以便清楚我如何使用 resultQuery() 方法来实现我想要的。我在问如何在 jOOQ 中以尽可能类型安全的方式实现这一点，因为我有更复杂的查询，我不知道是否可以通过不使用 PostgreSQL to_json() 函数来实现。例如，我想在 jOOQ 中创建类似 this 的内容，例如 bytefish.de 网站提交链接的“04_create_functions.sql”部分。
get_image
--------------------------------------------------------------
{"imageid" : 1,
"hash" : "a3b0c44",
"description" : "Some Description",
"created_on" : "2015-03-09T22:00:45.111",
"comments" : [{"commentid":1, "imageid":1, "text":"Awesome!", "createdon":"2015-03-09T22:58:47.783"},
{"commentid":2, "imageid":1, "text":"This is just a second comment.", "createdon" : "2015-03-09T22:58:47.783"}],
"tags" : [{"tagid":1,"name":"Cool"},
{"tagid":2,"name":"Berlin"}]}
(1 row)
我正在尝试为（书）订单的报告做同样的事情，其中查询我涉及 8 个表（我没有在此处发布该查询，因为我试图解决 jOOQ 中更简单的问题，即创建 JsonArray)。
【问题讨论】：
标签： java json postgresql aggregate jooq