Jooq with SQL Server How to select top N results - sql-server

Question

In our project we are using two databases, one postgres and one mssql. We are using Jooq in order to query these DBs and with postgres everything was pretty straight forward!
But with mssql we are facing some troubles. The task is to select the top 10 values and let's say that we have the following java code:
DSL.using(conn)
.select(USE_CASE.asterisk())
.from(USE_CASE)
.where(USE_CASE.RECORD_ACTIVE.eq(true))
.orderBy(USE_CASE.CREATED_ON.desc())
.limit(10)
.offset(0)
.fetch(new UseCaseMapper()))
This works like a charm with postgres but on mssql we get the following error:
Execution exception[[CompletionException: org.jooq.exception.DataAccessException:
SQL [select "park"."dbo"."use_case".* from "park"."dbo"."use_case" where
"park"."dbo"."use_case"."record_active" = ?
order by "park"."dbo"."use_case"."created_on" desc limit ?];
Incorrect syntax near 'limit'.]]
I know that for mssql the equivalent query would be something like,
select top 10 *
from use_case
where record_active = true
order by created_on desc;
How can I change my java code to get the limit records in mssql?

Answer 1

Correct SQLDialect
The exception message hints at the fact that you're still using the PostgreSQL (or some other non-SQL Server) dialect as your catalogs/schemas/tables/columns are quoted using "double_quotes", instead of [brackets].
Just use SQLDialect.SQLSERVER instead, when running your query on SQL Server. The LIMIT 10 syntax will then be correctly translated to TOP 10.
jOOQ Professional Edition vs jOOQ Open Source Edition
From our posted error messages, it is not quite clear how you really configured your jOOQ integration, but if you're using DSL.using(Connection) without explicitly specifying the SQLDialect, and jOOQ doesn't correctly "guess" the appropriate SQLDialect, this can mostly be because of one of two reasons:
You're using some non-standard JDBC URL, which jOOQ doesn't recognise. It thus uses SQLDialect.DEFAULT, instead, which produces the wrong SQL syntax for your.
You're using the jOOQ Open Source Edition (Maven groupId org.jooq) instead of the jOOQ Professional Edition (Maven groupId org.jooq.pro, to be installed manually, as it is not distributed via Maven Central), which would also lead to jOOQ using SQLDialect.DEFAULT.
Notice: this can also happen by accident, e.g. as a transitive dependency that is being pulled in via Spring Boot or some other framework that already depends on the jOOQ Open Source Edition. In that case, you have to make sure to exclude that transitive dependency from ending up on your classpath. In Maven, you can display all your dependencies using mvn dependency:tree