Add Special Math Operators as a postgres til.

README.md

@@ -66,6 +66,7 @@ smart people at [Hashrocket](http://hashrocket.com/).
 - [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)
 - [Send A Command To psql](postgres/send-a-command-to-psql.md)
+- [Special Math Operators](postgres/special-math-operators.md)
 - [String Contains Another String](postgres/string-contains-another-string.md)
 - [Temporarily Disable Triggers](postgres/temporarily-disable-triggers.md)
 - [Temporary Tables](postgres/temporary-tables.md)

postgres/special-math-operators.md

@@ -0,0 +1,35 @@
+# Special Math Operators
+
+Postgres has all the mathematical operators you might expect in any
+programming language (e.g. `+`,`-`,`*`,`/`,`%`). It also has a few extras
+that you might not be expecting.
+
+Factorial Operator:
+
+```sql
+> select 5!;
+ ?column?
+----------
+      120
+(1 row)
+```
+
+Square Root Operator:
+
+```sql
+> select |/81;
+ ?column?
+----------
+        9
+(1 row)
+```
+
+Absolute Value Operator:
+
+```sql
+> select @ -23.4;
+ ?column?
+----------
+     23.4
+(1 row)
+```