Add Fizzbuzz With Common Table Expressions as a postgres til.

README.md

@@ -59,6 +59,7 @@ smart people at [Hashrocket](http://hashrocket.com/).
 - [Count Records By Type](postgres/count-records-by-type.md)
 - [Default Schema](postgres/default-schema.md)
 - [Extracting Nested JSON Data](postgres/extracting-nested-json-data.md)
+- [Fizzbuzz With Common Table Expressions](postgres/fizzbuzz-with-common-table-expressions.md)
 - [Generate Series Of Numbers](postgres/generate-series-of-numbers.md)
 - [Limit Execution Time Of Statements](postgres/limit-execution-time-of-statements.md)
 - [List All Columns Of A Specific Type](postgres/list-all-columns-of-a-specific-type.md)

postgres/fizzbuzz-with-common-table-expressions.md

@@ -0,0 +1,23 @@
+# Fizzbuzz With Common Table Expressions
+
+In learning about CTEs (common table expressions) in postgres, I discovered
+that you can do some interesting and powerful things using the `with
+recursive` construct. The following solves the fizzbuzz problem for integers
+up to 100
+
+```sql
+with recursive fizzbuzz (num,val) as (
+    select 0, ''
+    union
+    select (num + 1),
+      case
+      when (num + 1) % 15 = 0 then 'fizzbuzz'
+      when (num + 1) % 5  = 0 then 'buzz'
+      when (num + 1) % 3  = 0 then 'fizz'
+      else (num + 1)::text
+      end
+    from fizzbuzz
+    where num < 100
+)
+select val from fizzbuzz where num > 0;
+```