如何重新排列主键? [英] How to reorder a primary key?

问题描述

我有一张5700条记录的表格.主键是一个整数.现在我注意到一些值丢失了.像这样:

I have a table of 5700 records. The primary key is an integer. Now I noticed that some values are missing. Like this:

100 data
101 data 
102 data
104 data

103丢失.如何在一条SQL命令中更新所有行，以使顺序正确(在我的示例中，104变为103)?

103 is missing. How I can update all the rows so that the order becomes correct (104 becomes 103 in my example) in one SQL command?

推荐答案

不确定一个命令，但是您可以使用四个命令来实现:

Not sure about one command, but you can do it in four commands:

CREATE TABLE `temp` SELECT * FROM `orig_tbl`;
TRUNCATE `orig_tbl`;
-- counter doesn't reset in some old versions
ALTER TABLE `orig_tbl` AUTO_INCREMENT = 1; 
-- now we omit primary key column to let it seal the holes
INSERT INTO `orig_tbl` (`col1`, `col2`) SELECT `col1`, `col2` FROM `temp`;

除非您这样做是为了使随机选择记录变得更容易，否则您确实应该重新考虑您的方法.

Unless you're doing this to make it easier to select records randomly, you really should rethink your approach.

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