MySQL - On Update not taking expression

[Sibz]

CREATE TABLE foo (`modification_time` DATETIME ON UPDATE CURRENT_TIMESTAMP())

does not work

[Sibz]

I am trying to resolve this
rustanigans@2585a03

But unable to work out how to make the test:
https://github.com/rustanigans/sqlparser-rs/blob/2585a03b6d7e700e0fe619e53e641af05c86bf9a/tests/sqlparser_mysql.rs#L853-L875
Not sure on how to assert against an expr

Also the ColumnOption::DialectSpecific only takes vec of tokens, so I had to add one for this that takes an expr:
https://github.com/rustanigans/sqlparser-rs/blob/2585a03b6d7e700e0fe619e53e641af05c86bf9a/src/ast/ddl.rs#L378-L379

If anyone could provide a bit of guidance I will make a PR once resolved.

[alamb]

I think if you make a PR that is likely the best way to get guidance.

[AugustoFKL]

@Sibz looking at MySQL's CREATE TABLE doc (1), I couldn't find why you're trying to give it an expression, as MySQL seems to follow the standard when it comes to the ON UPDATE clause(2).

You're trying to add the ON UPDATE CURRENT_TIMESTAMP clause (3), which is a unique kind of parameter.

[1] : https://dev.mysql.com/doc/refman/8.0/en/create-table.html
[2] : https://jakewheat.github.io/sql-overview/sql-2016-foundation-grammar.html#update-rule
[3]: https://dev.mysql.com/doc/refman/8.0/en/timestamp-initialization.html

[Sibz]

Yes your right, it doesn't take an expression per se, only takes CURRENT_TIMESTAMP or NOW but something must be provided, currently it's broken as will not parse those key words.

[Sibz]

And further, we must support all synonyms of CURRENT_TIMESTAMP:
CURRENT_TIMESTAMP(), NOW(), LOCALTIME, LOCALTIME(), LOCALTIMESTAMP and LOCALTIMESTAMP()
Parse considers the ones without parenthesis keywords but the ones with as expressions.

I will review my code and test as soon as I have chance, though I am very busy these days.