Updating colums two Tables at a time

[Anon]

i need to update a column in two tables with the same value. They are joined tables (one to many): FILES and Comments.

this works:

UPDATE FILES
SET Is_Deleted='1'
WHERE File_Id='1'

Why not this?

UPDATE FILES, COMMENTS
SET FILES.Is_Deleted = '1',
COMMENTS.Is_Deleted = '1'
WHERE LEFT JOIN COMMENTS ON FILES.File_Id = COMMENTS.File_Id Where FILES.File_Id = '31'

[Anon]

Why not this?

Simply because sql doesn't define such behavior.

However, if you require the updates to be linked, such that
they only apply if the both succeed, just use a full-featured
database like PostgreSQL and use transactions:

begin;
update files set Is_Deleted='1' WHERE File_Id='1';
update comments set Is_Deleted='1' WHERE File_Id='1';
commit;