SQL Server，使用表作为队列

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我使用 SQL Server 2008 R2 作为排队机制.我将项目添加到表中，外部服务读取并处理这些项目.这很好用，但缺少一件事 - 我需要一种机制，我可以尝试从表中选择一行，如果没有，则阻塞直到有(最好在特定时间段内).

I'm using an SQL Server 2008 R2 as a queuing mechanism. I add items to the table, and an external service reads and processes these items. This works great, but is missing one thing - I need mechanism whereby I can attempt to select a single row from the table and, if there isn't one, block until there is (preferably for a specific period of time).

谁能就我如何实现这一目标提出建议?

Can anyone advise on how I might achieve this?

推荐答案

我需要一种我可以尝试的机制从表中选择一行并且，如果没有，则阻塞直到有(最好是针对特定的一段时间).

I need mechanism whereby I can attempt to select a single row from the table and, if there isn't one, block until there is (preferably for a specific period of time).

您可以每秒循环并检查新行:

You can loop and check for new rows every second:

while not exists (select * from QueueTable) begin wait for delay '00:01' end

免责声明:这不是我用于生产系统的代码，但它可以满足您的要求.

Disclaimer: this is not code I would use for a production system, but it does what you ask.