MySQL手动id增量

Question

我有以下查询：

SET @count = 0;
UPDATE `batch_b`
SET `batch_b`.`printid` = @count:=@count+1;
ORDER BY postal_zone, country, airmail,company;

PrintID是一个整数，默认值为0.这不是主键。 当我运行查询时，我希望给出一次增量值，但它只返回NULL。

Answer 1

使用括号包装增量值后，它可以正常工作。谢谢！

Set @counter := 0;
UPDATE `batch_b`
SET `batch_b`.`printid` = (@counter:=@counter+1)
ORDER BY postal_zone, country, airmail,company;