MySQL 如何替换特定表中特定字段中的所有 NULL 值？
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How do I replace all my NULL values in a particular field in a particular table?
提问by Valerie
I've looked all over the internet for my answer, and perhaps I'm just doing things wrong. I have a column in my MySQL table that I need to replace all the NULL values with a text string in my SQL Query using phpMyAdmin. I don't want the output to come out that way, I want to actually replace the null values with the text string.
我在互联网上寻找答案，也许我只是做错了。我的 MySQL 表中有一个列，我需要使用 phpMyAdmin 将 SQL 查询中的所有 NULL 值替换为文本字符串。我不希望输出以这种方式出现，我想用文本字符串实际替换空值。
I've tried
我试过了
UPDATE `tablename` SET fieldname = replace (fieldname, "", "textstring")
I've read up on
我已经阅读了
SELECT ISNULL(field,"replacetext)
But this only shows the output, but doesn't actually replace it in the table.
但这仅显示输出，而实际上并未在表中替换它。
I can't figure this out, and I've wasted so much time trying to find an answer.
我无法弄清楚这一点，我浪费了太多时间试图找到答案。
回答by Nylon Smile
update tablename set fieldname = "textstring" where fieldname is null;
回答by Raj
Have you tried
你有没有尝试过
UPDATE `tablename` SET fieldname = '' where fieldname is null
