#30 jpa basic: jpql - condition

hello-jpa/src/main/java/com/hello/jpa/query/Condition.java

@@ -0,0 +1,82 @@
+package com.hello.jpa.query;
+
+import com.hello.jpa.query.entity.Member;
+import com.hello.jpa.query.entity.MemberType;
+import com.hello.jpa.query.entity.Team;
+
+import javax.persistence.EntityManager;
+import javax.persistence.EntityManagerFactory;
+import javax.persistence.EntityTransaction;
+import javax.persistence.Persistence;
+import java.util.List;
+
+public class Condition {
+
+    public static void main(String[] args) {
+        EntityManagerFactory emf = Persistence.createEntityManagerFactory("hello");
+
+        EntityManager em = emf.createEntityManager();
+
+        EntityTransaction tx = em.getTransaction();
+        tx.begin();
+
+        try {
+            Team team = new Team();
+            team.setName("team");
+            em.persist(team);
+
+            Member member = new Member();
+            member.setName("member");
+            member.setAge(10);
+            member.setTeam(team);
+            member.setMemberType(MemberType.ADMIN);
+
+            em.persist(member);
+
+            Member member2 = new Member();
+            member2.setName(null);
+            member2.setAge(70);
+            member2.setTeam(team);
+            member2.setMemberType(MemberType.USER);
+
+            em.persist(member2);
+
+            em.flush();
+            em.clear();
+
+            List<String> result = em.createQuery(
+                            "select " +
+                                    "case when m.age <= 10 then '학생요금' " +
+                                    "when m.age >= 60 then '경로요금' else '일반요금' end  from Member m",
+                            String.class
+                    )
+                    .getResultList();
+
+            result.forEach(System.out::println);
+
+            List<String> result2 = em.createQuery(
+                            "select coalesce(m.name, '이름 없는 회원') from Member m",
+                            String.class
+                    )
+                    .getResultList();
+
+            result2.forEach(System.out::println);
+
+            List<String> result3 = em.createQuery(
+                            "select nullif(m.name, 'member') from Member m",
+                            String.class
+                    )
+                    .getResultList();
+
+            result3.forEach(System.out::println);
+
+            tx.commit();
+        } catch (Exception e) {
+            tx.rollback();
+        } finally {
+            em.close();
+        }
+
+        emf.close();
+    }
+}