Null (MySQL)

Controleren op null

select * from product_tmp where filepath is null;

Controleren op niet-null:

select * from product_tmp where filepath is not null;

Controleren op een lege string:

select * from products if filepath=;

Controleren op een niet-lege string:

select * from products if filepath<>;

of

select * from products if filepath!=;

Null vervangen in expressies

Bv.:

ifnull(tool_subtype,"")

Null toekennen

Voorbeelden:

update root_tmp
set ean_id = null;

update root_tmp
set 

	ean_id = null,
	sku    = null;

Bronnen

• http://dev.mysql.com/doc/refman/5.7/en/comparison-operators.html
• http://stackoverflow.com/questions/8470813/how-do-i-check-if-a-column-is-empty-or-null-in-mysql
• http://stackoverflow.com/questions/9314353/set-value-to-null-in-mysql