Here's the commit where the "UPDATE .. SET ROW (col, ..) = (col, ..)" syntax was added as an alternative to "UPDATE .. SET (col, ..) = (col, ..)": https://git.p

Here's the commit where the "UPDATE .. SET ROW (col, ..) = (col, ..)" syntax was added as an alternative to "UPDATE .. SET (col, ..) = (col, ..)": https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=906bfcad7ba7cb3863fe0e2a7810be8e3cd84fbd https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit... I don't quite understand the commit message, but I think the new syntax resolves some ambiguity in the grammar in an edge case. From the diff of src/test/regress/sql/update.sql: -- *-expansion should work in this context: UPDATE update_test SET (a,b) = ROW(v.*) FROM (VALUES(21, 100)) AS v(i, j) WHERE update_test.a = v.i; -- you might expect this to work, but syntactically it's not a RowExpr: UPDATE update_test SET (a,b) = (v.*) FROM (VALUES(21, 101)) AS v(i, j) WHERE update_test.a = v.i;