如何使用jOOQ使用自定义函数解析SQL字符串？

Question

I am trying to parse SQL string with jOOQ SQL parser . The SQL contains self defined functions like this:

select dateadd([*]'20190809', 'yyyymmdd', 1) from table1

It can't be parsed with any dialect. I want to get the select fields and manipulate the limit-offset clause.

Is there any way to achieve this?

Answer 1

The somewhat standard DATEADD() function ( DATE_ADD() in some SQL dialects) takes very many different forms, depending on the specific SQL dialect.

jOOQ's SQL parser currently only supports one of these variations: DATEADD(<datepart>, <interval>, <date>) , which corresponds to the syntax in SQL Server (and some other dialects).

Applied to your example (assuming you want to add one day) this would be:

select dateadd(DAY, 1, date '2019-08-09') from table1

Note that the '20190809' isn't a proper date literal in most dialects, which is why I substituted it with date '2019-08-09' .

Also note that you can play around with these things using the jOOQ translator .

Assuming you have your own user-defined stored procedure also called DATEADD , then you are indeed out of luck, as jOOQ's parser attempts to parse the expression as described above. With any other name (eg DATEADD1 ) jOOQ's parser would not have any problem parsing this expression. You might however want to configure how jOOQ should deal with unknown functions .