EXISTS clause in create / drop table?

[stevegoobermanhill]

Great parser - thanks for all the effort.

It doesn't look like EXISTS clauses in table creation and deletion are supported right now. Such as

DROP TABLE IF EXISTS foo;
CREATE TABLE foo (...);

Is this correct. If so, are there any plans to support this functionality (the example on the homepage throws an error if an EXISTS clause is used in this context).

Thanks,
Steve

[JakeWheat]

Hi Steve,

The system doesn't support this syntax, and there are no plans to support it on my side, but a patch would be welcome!

[stevegoobermanhill]

Hi Jake, no worries - actually I'm not that interested in that particular bit of syntax (but I might be interested in the syntax around CREATE INDEX). Is there a way of getting the parser (parseStatements) to ignore unsupported statements - I'm interested in doing some work with some big database schema (hundreds of tables in each DB). I'm fairly new to Haskell (although I have experience wit h a wide range of languages and styles starting from Commodore BASIC in about 1979) - so I may take a look at any new functionality that might be useful when I have a chance. All the best, Steve

…

________________________________ From: Jake Wheat <[email protected]> Sent: 16 November 2019 11:46 To: JakeWheat/simple-sql-parser <[email protected]> Cc: Gooberman-Hill, Stephen <[email protected]>; Author <[email protected]> Subject: Re: [JakeWheat/simple-sql-parser] EXISTS clause in create / drop table? (#27) CAUTION: This email originated from outside of the organisation. Do not click links or open attachments unless you recognise the sender and know the content is safe. Hi Steve, The system doesn't support this syntax, and there are no plans to support it on my side, but a patch would be welcome! — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub<#27?email_source=notifications&email_token=ACGXHQ7AIHSWIDEOISYBH2TQT7MS7A5CNFSM4JM5QIZ2YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEEHPVNQ#issuecomment-554629814>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/ACGXHQ3OV6VTLTGFU42DMI3QT7MS7ANCNFSM4JM5QIZQ>. Amey plc is a company registered in England and Wales. Registered Office: Chancery Exchange, 10 Furnival Street, London, EC4A 1AB. Registered Number: 4736639. For particulars of companies within the Amey Group, please visit http://www.amey.co.uk/Home/Companyparticulars/tabid/182/Default.aspx. This email and accompanying attachments may contain confidential or privileged information and are for the sole use of the intended recipient(s). If you are not the intended recipient, you are notified that any use, dissemination, distribution or copying of this email or accompanying attachments is prohibited. If you received this email in error, please notify us immediately and delete all copies of this email and accompanying attachments. Email does not guarantee the confidentiality, completeness or proper receipt of the messages sent and is susceptible to alteration. Please note that Amey monitors incoming and outgoing emails for compliance with its Security Policies. This includes scanning emails for computer viruses.

[JakeWheat]

I have a tutorial on implementing SQL parsing in Haskell!
http://jakewheat.github.io/intro_to_parsing/

Is there a way of getting the parser (parseStatements) to ignore unsupported statements

This is an interesting idea I didn't consider before. I will have a think about it. Maybe you can get a long way with splitting your SQL source on ';' characters then parsing each string separately?

There is a fork of parsec called megaparsec which supports this sort of thing more explicitly in the parser (I understand there is also a more proper way of doing it, in the uu-parsinglib library).