I'm not sure either of the before or after versions of the SQL look correct. It certainly doesn't match the syntax in the PostgreSQL documentation: the use of commas to specify multiple tables is only defined for the top level -- not within join expressions.
I'm not even sure what "a LEFT JOIN (b, c) ON condition" means. How are you expecting "b" and "c" to be combined?
I'm not sure either of the before or after versions of the SQL look correct. It certainly doesn't match the syntax in the PostgreSQL documentation: the use of commas to specify multiple tables is only defined for the top level -- not within join expressions.
I'm not even sure what "a LEFT JOIN (b, c) ON condition" means. How are you expecting "b" and "c" to be combined?