Question

我有一个包含超过60列的“user”表。列的名称之一是“用户名”

我想删除用户名字段为空或 NULL

的行

我该怎么做？

谢谢！

Answer 1

试试这个

DELETE FROM user WHERE username IS NULL;

或

DELETE FROM user WHERE username = '';

Problems with NULL Values

Answer 2

如果要删除包含username = NULL的所有行，并且其中username为空字符串（“”）以及

然后

DELETE FROM table_name WHERE username IS NULL OR username = '';

建议首先执行SELECT查询，条件与您要在DELETE查询中使用的WHERE条件相同，以查看哪些行将被删除：

SELECT * FROM table_name WHERE username IS  NULL OR username = "";

Answer 3

在这里，我为任何类型的SQL表创建了一个脚本。请复制此存储过程并在您的环境中创建该存储过程，然后使用Table运行该存储过程。

exec [dbo].[SP_RemoveNullValues] 'Your_Table_Name'

存储过程

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
--akila liyanaarachchi
Create procedure [dbo].[SP_RemoveNullValues](@PTableName Varchar(50) ) as 
begin


DECLARE Cussor CURSOR FOR 
SELECT COLUMN_NAME,TABLE_NAME,DATA_TYPE
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = @PTableName  

OPEN Cussor;

Declare @ColumnName Varchar(50)
Declare @TableName  Varchar(50)
Declare @DataType Varchar(50)
Declare @Flage  int 

FETCH NEXT FROM Cussor INTO @ColumnName,@TableName,@DataType
WHILE @@FETCH_STATUS = 0
BEGIN

set @Flage=0


If(@DataType in('bigint','numeric','bit','smallint','decimal','smallmoney','int','tinyint','money','float','real'))
begin
set @Flage=1
end 
If(@DataType in('date','atetimeoffset','datetime2','smalldatetime','datetime','time'))
begin
set @Flage=2
end 
If(@DataType in('char','varchar','text','nchar','nvarchar','ntext'))
begin
set @Flage=3
end 

If(@DataType in('binary','varbinary'))
begin
set @Flage=4
end 



DECLARE @SQL VARCHAR(MAX) 

if  (@Flage in(1,4))
begin 

SET @SQL ='  update ['+@TableName+'] set ['+@ColumnName+']=0 where ['+@ColumnName+'] is null'
end 

if  (@Flage =3)
begin 

SET @SQL ='  update ['+@TableName+'] set ['+@ColumnName+'] = '''' where ['+@ColumnName+'] is null '
end 

if  (@Flage =2)
begin 

SET @SQL ='  update ['+@TableName+'] set ['+@ColumnName+'] ='+'''1901-01-01 00:00:00.000'''+' where ['+@ColumnName+'] is null '
end 


EXEC(@SQL)



FETCH NEXT FROM Cussor INTO @ColumnName,@TableName,@DataType
END

CLOSE Cussor
DEALLOCATE Cussor

END

mysql - 从表中删除空值行

3 个答案: