MySQL - Removing null value rows from table - mysql

Question

I have a table "user" with over 60 columns. One of the column's name is "username"
I want to remove the rows where the username field is empty or NULL
How can I do this?
Thank you!

Answer 1

Try this
DELETE FROM user WHERE username IS NULL;
or
DELETE FROM user WHERE username = '';
Problems with NULL Values

Answer 2

If you want to delete all those rows containing username = NULL AND where username is empty string ("") as well
then
DELETE FROM table_name WHERE username IS NULL OR username = '';
It is advised to first do a SELECT query with same WHERE condition as that you are going to use in DELETE query to see which rows will be deleted:
SELECT * FROM table_name WHERE username IS NULL OR username = "";

Answer 3

Here I have created a script for any kind of SQL table. please copy this stored procedure and create this on your Environment and run this stored procedure with your Table.
exec [dbo].[SP_RemoveNullValues] 'Your_Table_Name'
stored procedure
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