Re: [SQL] How match percent sign in SELECT using LIKE?
От | Bruce Momjian |
---|---|
Тема | Re: [SQL] How match percent sign in SELECT using LIKE? |
Дата | |
Msg-id | 199903162226.RAA20904@candle.pha.pa.us обсуждение исходный текст |
Ответ на | Re: [SQL] How match percent sign in SELECT using LIKE? (Zalman Stern <zalman@netcom.com>) |
Ответы |
Re: [SQL] How match percent sign in SELECT using LIKE?
Re: [SQL] How match percent sign in SELECT using LIKE? |
Список | pgsql-sql |
> One useful and probably not too hard thing to do is to allow ESCAPE '\' on > the end of the LIKE clause. Any character other than '\' will be an error. > This allows Postgres users to write compliant SQL code that can be used > with other databases. This is an excellent idea, I will implement it. > > Another approach is to "rewrite" the match string at parse time. If it is a > known constant, you can do the whole job there. Otherwise, you'd insert an > extra node in the parse tree which does the rewrite just before calling hte > "~~" operator. (I am assuming the match string can be a general expression > and that you can add a function of two arguments which rewrites the first > argument using the second argument as the escape character. This is of > course not the utmost of micro efficiency, but I doubt it would matter > much.) > > But I don't have in depth knowledge of the Postgres SQL parser and > evaluator so I may be way off base. That is also an excellent idea. Just convert their escape to \ inside the parser. Of course, they still have to use \\ to get a \, as in any string. Great idea. -- Bruce Momjian | http://www.op.net/~candle maillist@candle.pha.pa.us | (610) 853-3000 + If your life is a hard drive, | 830 Blythe Avenue + Christ can be your backup. | Drexel Hill, Pennsylvania 19026
В списке pgsql-sql по дате отправления: