android - 更新 SQLite 中的前 n 条记录

Question

我想从 Android 应用程序更新我的 SQLite 数据库中的前 n 条记录。以下是我迄今为止尝试过的查询。我在 order 附近遇到语法错误。

update label set label_is_used = 1 where label_name !='temp' and label_cnt != 0 order by label_cnt desc limit 3
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update label set label_is_used = 1 where label_name !='temp' and label_cnt != 0 order by label_cnt limit 3

来自docs ，这应该符合语法。

我哪里错了？

Answer 1

documentation you linked to说:

If SQLite is built with the SQLITE_ENABLE_UPDATE_DELETE_LIMIT compile-time option then the syntax of the UPDATE statement is extended with optional ORDER BY and LIMIT clauses

默认情况下不启用该选项，当然在 Android 上也不启用。

作为解决方法，确定要在子查询中更新的记录:

UPDATE label
SET label_is_used = 1
WHERE label_id IN (SELECT label_id   -- or whatever you use as ID
                   FROM label
                   WHERE label_name != 'temp'
                     AND label_cnt != 0
                   ORDER BY label_cnt DESC
                   LIMIT 3);