Create occupations.sql

Author: erjan

hackerrank_sql_practice/occupations.sql

@@ -0,0 +1,23 @@
+
+/* 
+Pivot the Occupation column in OCCUPATIONS so that each Name is sorted alphabetically and displayed underneath its corresponding Occupation. 
+The output column headers should be Doctor, Professor, Singer, and Actor, respectively.
+
+Note: Print NULL when there are no more names corresponding to an occupation.
+*/
+
+set @r1=0, @r2=0, @r3=0, @r4=0;
+select min(Doctor), min(Professor), min(Singer), min(Actor)
+from(
+  select case when Occupation='Doctor' then (@r1:=@r1+1)
+            when Occupation='Professor' then (@r2:=@r2+1)
+            when Occupation='Singer' then (@r3:=@r3+1)
+            when Occupation='Actor' then (@r4:=@r4+1) end as RowNumber,
+    case when Occupation='Doctor' then Name end as Doctor,
+    case when Occupation='Professor' then Name end as Professor,
+    case when Occupation='Singer' then Name end as Singer,
+    case when Occupation='Actor' then Name end as Actor
+  from OCCUPATIONS
+  order by Name
+) temp
+group by RowNumber;