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How to use DSL.coalesce with lists of fields?

Using Jooq, I am trying to fetch from a table by id first, if no matches found, then fetch by handle again.
And I want all fields of the returned rows, not just one.
Field<?> firstMatch = DSL.select(Tables.MY_TABLE.fields())
.from(Tables.MY_TABLE.fields())
.where(Tables.MY_TABLE.ID.eq(id))
.asfield(); // This is wrong, because it supports only one field, but above we selected Tables.MY_TABLE.fields(), which is plural.
Field<?> secondMatch = DSL.select(Tables.MY_TABLE.fields())
.from(Tables.MY_TABLE.fields())
.where(Tables.MY_TABLE.HANDLE.eq(handle))
.asfield(); // Same as above.
dslContext.select(DSL.coalesce(firstMatch, secondMatch))
.fetchInto(MyClass.class);
Due to the mistake mentioned above in the code, the following error occurs:
Can only use single-column ResultProviderQuery as a field
I am wondering how to make firstMatch and secondMatch two lists of fields, instead of two fields?
I tried
Field<?>[] secondMatch = DSL.select(Tables.MY_TABLE.fields())
.from(Tables.MY_TABLE.fields())
.where(Tables.MY_TABLE.HANDLE.eq(handle))
.fields();
but the following error occurred in the line containing DSL.coalesce
Type interface org.jooq.Field is not supported in dialect DEFAULT
Thanks in advance!

This sounds much more like something you'd do with a simple OR?
dslContext.selectFrom(MY_TABLE)
.where(MY_TABLE.ID.eq(id))
// The ne(id) part might not be required...
.or(MY_TABLE.ID.ne(id).and(MY_TABLE.HANDLE.eq(handle))
.fetchInto(MyClass.class);
If the two result sets should be completely exclusive, then you can do this:
dslContext.selectFrom(MY_TABLE)
.where(MY_TABLE.ID.eq(id))
.or(MY_TABLE.HANDLE.eq(handle).and(notExists(
selectFrom(MY_TABLE).where(MY_TABLE.ID.eq(id))
)))
.fetchInto(MyClass.class);
If on your database product, a query using OR doesn't perform well, you can write an equivalent query with UNION ALL, which might perform better.

How to get category by name?

I recently work with commerce tools platform and I have such a question.
I have this query:
CompletionStage<List<Category>> stage = QueryExecutionUtils.queryAll(client, CategoryQuery.of().byName(Locale.ENGLISH, "cat1"));
final CompletableFuture<List<Category>> result = stage.toCompletableFuture();
return result.get().get(0);
Is there a way to return just a Category instead of List.get(0) and how it can be done?

Thanks for submitting this question. There is no unique constraint for the name field on categories. For this reason we cannot guarantee that the API will only return one result. With the name query you will get paged results and will have to pull the first entry from the list. Both key and id are both unique so you could query for either of those and get just the unique category. You can view the representation of categories in the docs here. https://docs.commercetools.com/http-api-projects-categories#category
Hope this helps!

How to use IN clause with Mybatis Annotation inside SQL Provider

I have seen links pointing to the solution but most relevant is How to use Annotations with iBatis (myBatis) for an IN query?
but even this doesn't provide solution for Oracle driver.
public String getEmployees(Map<String, Object> params){
//Value hold by params params={empId={123,345,667,888}}
StringBuilder sql=new StringBuilder();
sql.append("Select * from employee where emp_id in (#{empId}");
Mybatis substitute the values from the params.
But when the value is substituted the query becomes some thing below.
Select * from employee where emp_id in ('123,345,667,888');
Which is a invalid Query as mybatis has added the single quotes in the query.
How should I handle this issue for a fix?
I cannot concatenate the values because to prevent SQL Injection.

The accepted answer in How to use Annotations with iBatis (myBatis) for an IN query? gives a solution working for postgres, a string representation of the list/array is passed and converted by the database.
Oracle does not support this. The list must be iterared to bind every value.
In my opinion, what you are looking for is Dynamic SQL, explained by LordOfThePigs in the next answer. Adapted to this case would be:
#Select({"<script>",
"SELECT *",
"FROM employee",
"WHERE emp_id IN",
"<foreach item='emp' collection='empId'",
"open='(' separator=', ' close=')'>",
"#{emp}",
"</foreach>",
"</script>"})
List<Employee selectEmployees(Map<String, Object> params);
#SelectProvider provides SQL string built in Java. But binding parameters become much more tedious.

Spring Batch Paging with sortKeys and parameter values

I have a Spring Batch project running in Spring Boot that is working perfectly fine. For my reader I'm using JdbcPagingItemReader with a MySqlPagingQueryProvider.
#Bean
public ItemReader<Person> reader(DataSource dataSource) {
MySqlPagingQueryProvider provider = new MySqlPagingQueryProvider()
provider.setSelectClause(ScoringConstants.SCORING_SELECT_STATEMENT)
provider.setFromClause(ScoringConstants.SCORING_FROM_CLAUSE)
provider.setSortKeys("p.id": Order.ASCENDING)
JdbcPagingItemReader<Person> reader = new JdbcPagingItemReader<Person>()
reader.setRowMapper(new PersonRowMapper())
reader.setDataSource(dataSource)
reader.setQueryProvider(provider)
//Setting these caused the exception
reader.setParameterValues(
startDate: new Date() - 31,
endDate: new Date()
)
reader.afterPropertiesSet()
return reader
}
However, when I modified my query with some named parameters to replace previously hard coded date values and set these parameter values on the reader as shown above, I get the following exception on the second page read (the first page works fine because the _id parameter hasn't been made use of by the paging query provider):
org.springframework.dao.InvalidDataAccessApiUsageException: No value supplied for the SQL parameter '_id': No value registered for key '_id'
at org.springframework.jdbc.core.namedparam.NamedParameterUtils.buildValueArray(NamedParameterUtils.java:336)
at org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate.getPreparedStatementCreator(NamedParameterJdbcTemplate.java:374)
at org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate.query(NamedParameterJdbcTemplate.java:192)
at org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate.query(NamedParameterJdbcTemplate.java:199)
at org.springframework.batch.item.database.JdbcPagingItemReader.doReadPage(JdbcPagingItemReader.java:218)
at org.springframework.batch.item.database.AbstractPagingItemReader.doRead(AbstractPagingItemReader.java:108)
Here is an example of the SQL, which has no WHERE clause by default. One does get created automatically when the second page is read:
select *, (select id from family f where date_created between :startDate and :endDate and f.creator_id = p.id) from person p
On the second page, the sql is modified to the following, however it seems that the named parameter for _id didn't get supplied:
select *, (select id from family f where date_created between :startDate and :endDate and f.creator_id = p.id) from person p WHERE id > :_id
I'm wondering if I simply can't use the MySqlPagingQueryProvider sort keys together with additional named parameters set in JdbcPagingItemReader. If not, what is the best alternative to solving this problem? I need to be able to supply parameters to the query and also page it (vs. using the cursor). Thank you!

I solved this problem with some intense debugging. It turns out that MySqlPagingQueryProvider utilizes a method getSortKeysWithoutAliases() when it builds up the SQL query to run for the first page and for subsequent pages. It therefore appends and (p.id > :_id) instead of and (p.id > :_p.id). Later on, when the second page sort values are created and stored in JdbcPagingItemReader's startAfterValues field it will use the original "p.id" String specified and eventually put into the named parameter map the pair ("_p.id",10). However, when the reader tries to fill in _id in the query, it doesn't exist because the reader used the non-alias removed key.
Long story short, I had to remove the alias reference when defining my sort keys.
provider.setSortKeys("p.id": Order.ASCENDING)
had to change to in order for everything to work nicely together
provider.setSortKeys("id": Order.ASCENDING)

I had the same issue and got another possible solution.
My table T has a primary key field INTERNAL_ID.
The query in JdbcPagingItemReader was like this:
SELECT INTERNAL_ID, ... FROM T WHERE ... ORDER BY INTERNAL_ID ASC
So, the key is: in some conditions, the query didn't return results, and then, raised the error above No value supplied for...
The solution is:
Check in a Spring Batch decider element if there are rows.
If it is, continue with chunk: reader-processor-writer.
It it's not, go to another step.
Please, note that they are two different scenarios:
At the beginning, there are rows. You get them by paging and finally, there are no more rows. This has no problem and decider trick is not required.
At the beginning, there are no rows. Then, this error raised, and the decider solved it.
Hope this helps.

Spring JdbcTemplate's queryForList() with many args is not readable; SQLQuery don't give me list with column names

Note: This may be a simple question but I can't find a short way to make it clear. So, sorry for this long question.
In a project I am responsible, I use Spring 2.5, Hibernate 3.3.2 as middleware and Oracle database. As database is related to many other projects, some queries as really very complicated and I can't get a solution with Hibernate's solutions (HQL, Criteria, etc...). So I feel more comfortable with JdbcTemplate's queryForX() methods, as an example;
String sql = "select * from myTable";
jdbc.queryForList(sql);
Sure there are mostly "where" conditions and params indeed:
jdbc.querForList(sql, new Object[]{obj1,obj2,obj3 /* and many more arguments... */})
In this case, I must write question marks "?" for my parameters, so my SQL query string turns out some messy and hard to read; something like this:
select t1.col1, t2.col2, t1.col, --...some cols ,
sum(nvl(some_col1,?)-nvl(other_col2,?)) over (partition by col1,col2,col3,col4) sum_of_cols
from weird_table t1, another_table t2
where t1.col20=? and sum_of_cols>? and t1.col3=t2.col3 --and many ?'s...
and not exists (
select ? from boring_table t3 where -- many ?'s
)
--group by and order by order by etc
So now, which question mark is for which parameter? It is obvious but hard to read. But there are some other solutions for binded params like:
select * from a_table t where t.col1= :col1 and t.col2= :col2 -- and many more ":param"s
For this type query, we can write if it were Hibernate:
Query q = hibernateTemplate.createQuery();
q.setString("col1","a value");
q.setInteger("col2", 3);
I think it is more readable and easy to understand which value is what. I know I can do this with SQLQuery;
SQLQuery sq = hibernateTemplate.createSQLQuery();
/* same as above setInteger() etc. */
But this sq.list() gives me a list without a column name. so I have a basic array which is difficult to use:
[[1,2,"a"],[1,2,"b"], ...]
But with queryForList() I get better one:
[{COL1=1,COL2=2,COL3="a"},{COL1=1,COL2=2,COL3="b"},...]
So if I use queryForList(), I must write a very messy params Object;
or I use SQLQuery and then I have to get my list without a map as column names.
Is there a simple solution with mapped list using more readable param setting (like query.setX()) ?

Well you can use NamedParameterJdbcTemplate to do just that
Heres a sample
String query = "INSERT INTO FORUMS (FORUM_ID, FORUM_NAME, FORUM_DESC)
VALUES (:forumId,:forumName,:forumDesc)";
Map namedParameters = new HashMap();
namedParameters.put("forumId", Integer.valueOf(forum.getForumId()));
namedParameters.put("forumName", forum.getForumName());
namedParameters.put("forumDesc", forum.getForumDesc());
namedParameterJdbcTemplate.update(query, namedParameters);
You check the complete example with the source code in the below link
Spring NamedParameterJdbcTemplate Tutorial