DataIntegrityViolation Exception [Operand should contain 1 column(s)]

This occurs when there are multiple elements in a collection in the query parameter, e.g., ‘WHERE IN (:employeeNames)’. Here, if the List<String> employeeNames has exactly one element, the query runs fine; however, for more than one element, the query fails.

I am using Hibernate 6.3.1

You’re using the wrong syntax. If you want to use the multi-valued-parameter IN predicate, you have to remove the parenthesis.