Susanne Ebrecht <[EMAIL PROTECTED]> writes: > here is a patch that extends update syntax following the sql standard. > The patch includes sgml documentation, too.
> UPDATE table SET (col1, col2, ...) = (val1, val2, ...), > (colm, coln, ...) = (valm, valn, ...), ...; This is a cute hack, but it does only a small part of what I think the spec says. In the first place, the SQL syntax is pretty clear that you can combine simple and multiple assignment in the same UPDATE: <update statement: searched> ::= UPDATE <target table> SET <set clause list> [ WHERE <search condition> ] <set clause list> ::= <set clause> [ { <comma> <set clause> }... ] <set clause> ::= <multiple column assignment> | <set target> <equals operator> <update source> <multiple column assignment> ::= <set target list> <equals operator> <assigned row> <set target list> ::= <left paren> <set target> [ { <comma> <set target> } ... ] <right paren> The patch doesn't do that, but it wouldn't be too hard to fix. The more serious problem is that <assigned row> ::= <contextually typed row value expression> and <contextually typed row value expression> is supposed to be pretty much anything that can generate a row. The patch as you have it provides nothing more than syntactic sugar for something people can do anyway. The reason people want this syntax is that they expect to be able to write, say, UPDATE mytab SET (foo, bar, baz) = (SELECT alpha, beta, gamma FROM othertab WHERE key = mytab.key); and with something like that you can't break apart the row-valued expression in the grammar. So in reality the feature has to propagate much further into the backend than this. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly