我有一种情况，我更新了bigint[] 类型的Postgres 表列。每当触发 update 查询时，该数组内部应该有唯一的数字。
查询如下
UPDATE book_shelf
SET book_id = book_id || array[CAST(:bookID AS BIGINT)], updated_at = now()
WHERE user_id = :userID AND shelf_name = :shelfName
当上述查询被触发时，它只是将数字添加到我不想发生的数组中。它应该只包含唯一值。请帮帮我。
【问题讨论】：
标签： spring postgresql hibernate spring-data-jpa
你可以在添加之前检查它是否存在于数组中：
UPDATE book_shelf
SET book_id = CASE WHEN CAST(:bookID AS BIGINT) = ANY(book_id) THEN book_id ELSE ARRAY_APPEND(book_id, CAST(:bookID AS BIGINT)) END, updated_at = now()
WHERE user_id = :userID AND shelf_name = :shelfName
当然，如果updated_at 应该只在book_id 实际更新时才设置，然后将检查放在 WHERE 子句中，这样就不会不必要地更新：
UPDATE book_shelf
SET book_id = ARRAY_APPEND(book_id, CAST(:bookID AS BIGINT)), updated_at = now()
WHERE user_id = :userID
AND shelf_name = :shelfName
AND NOT CAST(:bookID AS BIGINT) = ANY(book_id)
【讨论】：