Datatypes

Author: clarklindev

README.md

@@ -72,6 +72,10 @@ completion date: 2021-10-16
   + [LEAST](#least)
   + [CASE](#case)
 
+---
+[10. PostgreSQL](#10-postgresql)
+  + [Installation](#installation)
+
 ---
 ###### <div style="text-align:right">[table of contents](#table-of-contents)</div>
 ## 1. Basics
@@ -978,6 +982,7 @@ SELECT
 )
 ```
 ---
+###### <div style="text-align:right">[table of contents](#table-of-contents)</div>
 
 ## 8. Destinct
 SQL keyword: DESTINCT
@@ -1001,6 +1006,9 @@ FROM products;
 ```
 
 ---
+
+###### <div style="text-align:right">[table of contents](#table-of-contents)</div>
+
 ## 9. Utility Operators, Keywords, and Functions
 
 #### GREATEST
@@ -1037,4 +1045,105 @@ SELECT
     ELSE 'cheap'
   END
 FROM products;
-```
+```
+
+---
+---
+###### <div style="text-align:right">[table of contents](#table-of-contents)</div>
+
+## 10. PostgreSQL 
+* Installing postgreSQL installs pgadmin.
+* Pgadmin is a web-based tool to manage and inspect a postgres database.
+* One postgres server can have multiple databases.
+* One app usually associated with one database.
+* use Query Editor to test SQL
+
+#### Installation
+
+* installation https://www.enterprisedb.com/downloads/postgres-postgresql-downloads
+* during install -> uncheck stack builder
+* password is password for local machine
+* run pgAdmin 4 -> password is to access pgadmin
+* clicking on servers -> requested password is password for localmachine.
+
+### Data types Categories
+#### most used:
+##### Numbers
+  * Numbers without any decimal points: (smallint, integer, bigint)
+  * No decimal point, auto increment: (smallserial, serial, bigserial)
+  * Number with decimal points: (decimal, numeric, real, double precision, float)
+
+  (RULES):
+  * SERIAL - id column on any table
+  * INTEGER - store number without decimal
+  * NUMERIC - store number with decimal - data needs to be accurate (bank balance, scientific calculations)
+  * DOUBLE PRECISION - store number with decimal - data doesnt need to be accurate (floating point math - eg. calculations result in something like 1.001358e-05)
+
+##### Character
+No performance benefits between types
+
+  * CHAR(4) - store some characters, length will always be 4 even if postgres has to add spaces
+  * VARCHAR(40) - store a string up to 40 chars, automatically remove extra chars
+  * VARCHAR - store any length of string
+  * TEXT - Store any lenght of string
+
+##### Boolean
+  * TRUE ('true', 'yes', 'on', 1, 't', 'y')
+  * FALSE ('false', 'no', 'off', 0, 'f', 'n')
+  * NULL (null)
+
+##### Date
+Can provide string in almost any format and postgres will do conversion
+can specify something to be date by explicitly giving a data type with '::DATE'
+
+```SQL
+SELECT('NOV 20 1980'::DATE);
+```
+  * 1980-11-20 -> 1980-11-20
+  * NOV-20-1980 -> 1980-11-20
+  * 20-Nov-1980 -> 1980-11-20
+  * 1980-November-20 -> 1980-11-20
+  * November 20, 1980 -> 1980-11-20
+
+##### Time
+
+  * TIME or TIME WITHOUT TIME ZONE
+  * TIME WITH TIME ZONE (converts to UCT time)
+  * TIMESTAMP WITH TIME ZONE
+  
+```SQL
+  SELECT('01:23 AM'::TIME)
+  --13:23:00
+
+  SELECT('01:23 AM EST'::TIME WITH TIME ZONE)
+  --converted to 01:23-05:00 (the -05 means 5 hours behind UCT time)
+
+  SELECT('Nov-20-1980 05:23PM PST'::TIMESTAMP WITH TIME ZONE)
+  --converted to 1980-11-20 02:23:00-07 (date, time, UCT offset)
+
+```
+
+##### Interval
+Can do math calculations on intervals.
+Can mix INTERVAL with other TIME types.
+Think of interval as a duration of time
+  * 1 day
+  * 1 D
+  * 1 D 1 M 1 S
+
+
+```SQL
+SELECT ('1 D 20 H 30 M 45 S'::INTERVAL) - ('1 D'::INTERVAL)
+  --result is 20:30:45
+```
+
+
+#### other: 
+* Currency
+* arrays
+* geometric
+* range
+* xml
+* binary
+* json
+* UUID