如何在 MySQL 中删除空白行?
mysqlmysqli database更新于 2025/1/18 3:56:17
使用 delete 命令删除 MySQL 中的空白行。
语法如下
delete from yourTableName where yourColumnName=' ' OR yourColumnName IS NULL;
上述语法将删除空白行以及 NULL 行。
为了理解这个概念，让我们创建一个表。创建表的查询如下
mysql> create table deleteRowDemo -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> StudentName varchar(20) -> ); Query OK, 0 rows affected (0.57 sec)
使用 insert 命令在表中插入一些记录。
查询如下
mysql> insert into deleteRowDemo(StudentName) values('John');
Query OK, 1 row affected (0.13 sec)
mysql> insert into deleteRowDemo(StudentName) values('');
Query OK, 1 row affected (0.18 sec)
mysql> insert into deleteRowDemo(StudentName) values('');
Query OK, 1 row affected (0.14 sec)
mysql> insert into deleteRowDemo(StudentName) values(NULL);
Query OK, 1 row affected (0.13 sec)
mysql> insert into deleteRowDemo(StudentName) values('Carol');
Query OK, 1 row affected (0.13 sec)
mysql> insert into deleteRowDemo(StudentName) values('Bob');
Query OK, 1 row affected (0.14 sec)
mysql> insert into deleteRowDemo(StudentName) values('');
Query OK, 1 row affected (0.18 sec)
mysql> insert into deleteRowDemo(StudentName) values('David');
Query OK, 1 row affected (0.35 sec)
使用 select 语句显示表中的所有记录。
查询如下
mysql> select *from deleteRowDemo;
以下是输出 −
+----+-------------+ | Id | StudentName | +----+-------------+ | 1 | John | | 2 | | | 3 | | | 4 | NULL | | 5 | Carol | | 6 | Bob | | 7 | | | 8 | David | +----+-------------+ 8 rows in set (0.00 sec)
以下是删除空白行和 NULL 的查询
mysql> delete from deleteRowDemo where StudentName='' OR StudentName IS NULL; Query OK, 4 rows affected (0.18 sec))
现在让我们再次检查表记录。
查询如下
mysql> select *from deleteRowDemo;
以下是输出 −
+----+-------------+ | Id | StudentName | +----+-------------+ | 1 | John | | 5 | Carol | | 6 | Bob | | 8 | David | +----+-------------+ 4 rows in set (0.00 sec)
相关文章
有用资源
mysql 参考教程 - 该教程包含有关 mysql 的更多信息:https://www.cainiaomax.com/mysql/
