MySQL mySQL查询删除列中的空记录
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mySQL Query Remove Null Records in Column
提问by Michael Falciglia
I have a large mySQL database and I want to remove every record that is empty, not null in a certain column. What is the best way to do write a SQL query for this?
我有一个很大的 mySQL 数据库，我想删除某个列中的每条空记录，而不是空记录。为此编写 SQL 查询的最佳方法是什么？
Currently I have tried:
目前我已经尝试过：
DELETE FROM Businesses WHERE WEBADDRESS IS NULL
But it did not delete anything. There are 44,000 records and almost 80% of them are null in that column.
但它没有删除任何东西。该列中有 44,000 条记录，其中几乎 80% 为空。
回答by Matthew
DELETE FROM myTable WHERE myColumn IS NULL
Link to MySQL page for DELETE syntax: http://dev.mysql.com/doc/refman/5.7/en/delete.html
DELETE 语法的 MySQL 页面链接：http: //dev.mysql.com/doc/refman/5.7/en/delete.html
IF the column is not NULLbut just blank you would need to do something like:
如果该列不是NULL但只是空白，则需要执行以下操作：
DELETE FROM myTable WHERE myColumn = ''
Based on the information you also provided in the comments, the values are likely being loaded as empty ('') and not NULL: http://dev.mysql.com/doc/refman/5.7/en/problems-with-null.html
根据您还在评论中提供的信息，这些值可能被加载为空 ( '') 而不是NULL：http: //dev.mysql.com/doc/refman/5.7/en/problems-with-null.html
The second query should work.
第二个查询应该可以工作。
回答by juergen d
delete from your_table
where certain_column is null
回答by Purple
DELETE from `<tablename>`
WHERE `<columnname>` is null
回答by php
delete from table_name where column=''
回答by Ahsan Raza
delete from table_name where column_name is null; this query will definitely work for you.
从 table_name 中删除，其中 column_name 为空；这个查询肯定对你有用。
回答by Nevermore
Don't worry about count of data. Mysql can handle it. Just write:
不要担心数据的数量。Mysql 可以处理它。写就好了：
DELETE FROM `Businesses` WHERE `WEBADDRESS` = '';
