Add Compute The md5 Hash Of A String as a postgres til

README.md

@@ -7,7 +7,7 @@ variety of languages and technologies. These are things that don't really
 warrant a full blog post. These are mostly things I learn by pairing with
 smart people at [Hashrocket](http://hashrocket.com/).
 
-_406 TILs and counting..._
+_407 TILs and counting..._
 
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@@ -177,6 +177,7 @@ _406 TILs and counting..._
 - [Clear The Screen In psql](postgres/clear-the-screen-in-psql.md)
 - [Clear The Screen In psql (2)](postgres/clear-the-screen-in-psql-2.md)
 - [Compute Hashes With pgcrypto](postgres/compute-hashes-with-pgcrypto.md)
+- [Compute The md5 Hash Of A String](postgres/compute-the-md5-hash-of-a-string.md)
 - [Configure The Timezone](postgres/configure-the-timezone.md)
 - [Constructing A Range Of Dates](postgres/constructing-a-range-of-dates.md)
 - [Count Records By Type](postgres/count-records-by-type.md)

postgres/compute-the-md5-hash-of-a-string.md

@@ -0,0 +1,22 @@
+# Compute The md5 Hash Of A String
+
+One of the functions provided by PostgreSQL for working with string data is
+the `md5()` function. This function calculates the md5 hash of a given string.
+
+It works like this:
+
+```sql
+> select md5('Hello, World!');
+               md5
+----------------------------------
+ 65a8e27d8879283831b664bd8b7f0ad4
+
+> select md5('$3cr3tp4$$w0rd');
+               md5
+----------------------------------
+ bbabecfd4031211077473734bae7249f
+```
+
+There are more hashing algorithms provided by the `pgcrypto` extension. See
+[Compute Hashes With pgcrypto](postgres/compute-hashes-with-pgcrypto.md) for
+more details on that.