通过查询各种表中的多个字段进行更新

Question

我有以下表格：

book_tbl：

book_instance_id | book_type_id | library_instance_id | location_id | book_index
1                | 70000        | 2                   | 0           | 1
2                | 70000        | 2                   | 0           | 2
3                | 70000        | 2                   | 0           | 3
4                | 70000        | 3                   | 0           | 1
5                | 70000        | 3                   | 0           | 2
6                | 70000        | 3                   | 0           | 3
7                | 70000        | 4                   | 1           | 1
8                | 70000        | 4                   | 1           | 2
9                | 70000        | 4                   | 1           | 3

和library_tbl：

library_instance_id | library_type_id | location_id
2                   | 1000            | 0
3                   | 1001            | 0
4                   | 1000            | 1

我想更新book_type_id中的字段book_tbl仅针对library_type_id 1000

中的第一个元素（索引）

要检索此信息，我使用了sqlite查询：

SELECT * FROM ( ( SELECT *
                  FROM library_tbl
                  WHERE library_type_id=1000 ) t1
                join book_tbl t2 on t1.location_id=t2.location_id
                                AND t1.library_instance_id=t2.library_instance_id
                                AND book_index=1 )

如何使用上面的查询和UPDATE查询来更新第1行和第7行：

UPDATE book_tbl SET book_type_id=15000 WHERE ????

Answer 1

使用带有correlated subquery的EXISTS来检查相应的库行是否存在：

UPDATE book_tbl
SET book_type_id = 15000
WHERE EXISTS (SELECT 1
              FROM library_tbl
              WHERE library_type_id = 1000
                AND location_id         = book_tbl.location_id
                AND library_instance_id = book_tbl.library_instance_id)
  AND book_index = 1;