database - Update a double type column with NULL value in mysql

Question

I have the following table:

IDCode(bigint(20))	lng(double)
0000	NULL
NULL	NULL
0000	NULL
0000	NULL
NULL	NULL
0000	NULL

Answer 1

Why do you want to use ''?

You can just simply update the data without using ''.

i.e :

UPDATE profile SET lng = 1 WHERE IDCode IS NOT NULL;

This is the code I have tested on : https://paiza.io/projects/PWQZ8UXjGN6KDnMiFfXaKQ?language=mysql

create table profile(IDCode bigint(20), lng double);
insert into profile values(null, null);
insert into profile values(null, null);
insert into profile values(null, null);
insert into profile values(null, null);
insert into profile values(0000, null);
insert into profile values(0000, null);

UPDATE profile SET lng = 1 WHERE IDCode IS NOT NULL;
select * from profile;

Result

IDCode  lng
NULL    NULL
NULL    NULL
NULL    NULL
NULL    NULL
0   1
0   1