oracle 在 SQL 更新语句中使用子字符串
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Using substring in SQL update statement
提问by user3266259
I'm writing a SQL query that updates the CUST_NAME column by appending the the word "CHECKED to it. The column is only 100 characters long however and I'm going to run into errors if I have an already long customer name and try appending CHECKED to it. So I want to use the Substring function in sql, but kind of stumped. I want to be able to substring the CUST_NAME field if it will go over 100 characters with the appended word. How can I do that? Thank you
我正在编写一个 SQL 查询，通过将单词“CHECKED”附加到它来更新 CUST_NAME 列。但是，该列只有 100 个字符长，如果我的客户名称已经很长，我将遇到错误并尝试附加检查它。所以我想在 sql 中使用 Substring 函数，但有点难。如果 CUST_NAME 字段的附加单词超过 100 个字符，我希望能够对它进行子字符串化。我该怎么做？谢谢
UPDATE CUST_INFO cust
SET CUST_NAME = (CUST_NAME||'_CHECKED')
WHERE process_timestamp = null;
回答by Gordon Linoff
Here is one way:
这是一种方法：
UPDATE CUST_INFO cust
SET CUST_NAME = SUBSTR(CUST_NAME, 1, 92) || '_CHECKED'
WHERE process_timestamp is null;
Also, if you want to update any records, then use is nullrather than = null(the latter never evaluates to true).
此外，如果您想更新任何记录，请使用is null而不是= null（后者永远不会评估为真）。
Note: Not all databases have the left()function, you can use substr()or the equivalent instead.
注意：不是所有的数据库都有这个left()功能，你可以用substr()或 等效的来代替。
