Syntax
INNER
and
OUTER
are ignored.
FULL
is not implemented in MySQL.
“commajoin” (
FROM a,b WHERE a.x=b.y
) is frowned on; use
FROM a JOIN b ON a.x=b.y
instead.
FROM a JOIN b ON a.x=b.y includes rows that match in both tables.
FROM a LEFT JOIN b ON a.x=b.y includes all rows from
a
, plus matching data from
b
, or
NULLs
if there is no matching row.