From ac08df2ee7e9b2cff603b986e5deafeb3ab82d7d Mon Sep 17 00:00:00 2001
From: Timur Tarasenko <timur.tarasenko@gmail.com>
Date: Thu, 18 Oct 2018 10:27:58 -0500
Subject: [PATCH] Oralce PL/SQL examples of recursion (#91)

---
 03_recursion/plsql/01_countdown.sql | 22 ++++++++++++++++++++++
 03_recursion/plsql/02_greet.sql     | 28 ++++++++++++++++++++++++++++
 03_recursion/plsql/03_factorial.sql | 22 ++++++++++++++++++++++
 3 files changed, 72 insertions(+)
 create mode 100644 03_recursion/plsql/01_countdown.sql
 create mode 100644 03_recursion/plsql/02_greet.sql
 create mode 100644 03_recursion/plsql/03_factorial.sql

diff --git a/03_recursion/plsql/01_countdown.sql b/03_recursion/plsql/01_countdown.sql
new file mode 100644
index 0000000..640ed73
--- /dev/null
+++ b/03_recursion/plsql/01_countdown.sql
@@ -0,0 +1,22 @@
+SET SERVEROUTPUT ON
+DECLARE  
+   result NUMBER; 
+   
+FUNCTION countdown(x NUMBER)  
+RETURN NUMBER  
+IS  
+   f NUMBER;
+ 
+BEGIN  
+    dbms_output.put_line(x);
+   IF x <= 0  THEN  
+      return x;
+   ELSE  
+      f := countdown(x - 1);  
+   END IF;  
+RETURN f;  
+END;  
+   
+BEGIN  
+  result := countdown(5);  
+END; 
\ No newline at end of file
diff --git a/03_recursion/plsql/02_greet.sql b/03_recursion/plsql/02_greet.sql
new file mode 100644
index 0000000..f791c62
--- /dev/null
+++ b/03_recursion/plsql/02_greet.sql
@@ -0,0 +1,28 @@
+CREATE OR REPLACE PROCEDURE greet2(names IN VARCHAR2 ) 
+IS 
+BEGIN
+    dbms_output.put_line('how are you, ' || names || '?'); 
+END;
+/
+
+CREATE OR REPLACE PROCEDURE bye
+IS
+BEGIN
+    dbms_output.put_line('ok bye!');
+END;
+/
+ 
+CREATE OR REPLACE PROCEDURE greet(names IN VARCHAR2)
+IS
+BEGIN
+     dbms_output.put_line('hello, ' || names || '!');
+     greet2(names);
+     dbms_output.put_line('getting ready to say bye...');
+     bye();
+END;
+/
+
+SET SERVEROUTPUT ON  
+BEGIN  
+   greet('adit');
+END;  
\ No newline at end of file
diff --git a/03_recursion/plsql/03_factorial.sql b/03_recursion/plsql/03_factorial.sql
new file mode 100644
index 0000000..697dd93
--- /dev/null
+++ b/03_recursion/plsql/03_factorial.sql
@@ -0,0 +1,22 @@
+SET SERVEROUTPUT ON
+DECLARE  
+   result NUMBER; 
+
+FUNCTION factorial(x NUMBER)  
+RETURN NUMBER  
+IS  
+   f NUMBER;
+   
+BEGIN  
+   IF x = 0  THEN  
+      f := 1;
+   ELSE  
+      f := x * factorial(x - 1);  
+   END IF;  
+RETURN f;  
+END;  
+   
+BEGIN  
+  result := factorial(5);  
+  dbms_output.put_line(result);
+END;