只选择一半的记录 [英] Select only half the records

问题描述

我想弄清楚如何选择 ID 为空的一半记录.我想要一半，因为我将使用该结果集来更新另一个 ID 字段.然后我将使用该 ID 字段的另一个值更新其余部分.

I am trying to figure out how to select half the records where an ID is null. I want half because I am going to use that result set to update another ID field. Then I am going to update the rest with another value for that ID field.

所以基本上我想用一个数字更新一半的 someFieldID 记录，其余的用另一个数字更新，基本上将更新拆分为我想要更新的字段 someFieldID 的两个值.

So essentially I want to update half the records someFieldID with one number and the rest with another number splitting the update basically between two values for someFieldID the field I want to update.

推荐答案

在 oracle 中你可以使用 ROWNUM psuedocolumn.我相信在 sql server 中你可以使用 TOP.示例:

In oracle you can use the ROWNUM psuedocolumn. I believe in sql server you can use TOP. Example:

select TOP 50 PERCENT * from table

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