JdbcPagingItemReader not working with join query - spring-boot

Question

I have two tables table 1 and table 2. Both have same name id column.
As it's a left outer join query, I have to use aliases.
In sortKeys, If I mention id , error is
Caused by: org.postgresql.util.PSQLException: ERROR: column reference "id" is ambiguous
In sortKeys, If I mention t1.id , error is
Caused by: org.postgresql.util.PSQLException: The column name t1.id was not found in this ResultSet.
How to handle such queries?
I am using latest spring boot version 2.2.5.RELEASE
I have seen other posts related to this issue on stackoverflow. However, those are in older versions of spring batch and hence I should not face this issue.

Answer 1

One way you could solve this issue, is by adding the t1.id as projection and naming it something else, like :
select t1.id as id_t1 ....
and in your sortKeys add "id_t1".
Hope this helps

Answer 2

The answer by #youness.bout and another kind programmer worked for me. I've documented it here https://github.com/spring-projects/spring-batch/issues/1208#issuecomment-994234546. It appears to be a known issue in Spring Batch project.
Rewriting the answer here:
Using the same column name alias as that in column name in the select clause - t1.table1_column1 as 't1.table1_column1'
Enclosing the column name alias in single quote (') in the select clause - t1.table1_column1 as 't1.table1_column1'
Used the column name alias as the sort key - setSortKey("t1.table1_column1")
Here's what I did in kotlin
#Bean
#StepScope
fun readQueryProvider() = SqlPagingQueryProviderFactoryBean().apply {
setDataSource(dataSource)
setSelectClause("select t1.table1_column1 as 't1.table1_column1', t1.table1_column2,"
+ " t1.table1_column3, t2.table2_column2, t3.table3_column3")
setFromClause("table1 t1"
+ " inner join table2 t2 on t1.table1_column1 = t2.table2_column1"
+ " inner join table3 t3 on t2.table2_column2 = t3.table3_column2"
+ " inner join table4 t4 on t1.table1_column1 = t4.table4_column1")
setWhereClause("where t3.table3_column2 = :placeholder1"
+ " and t2.table2_column3 = :placeholder2 and t4.table4_column2 = :placeholder3")
setSortKey("t1.table1_column1")
}