PostgreSQL Datatypes

Following are a few common data types one can use in PostgreSQL:

1. Character datatypes:
   1. Char(n): fixed-length strings, blank padded in case string length is less than n.
   2. Varchar(n): variable length strings but within a certain limit. 
   3. Text: string values with no length constraint, i.e unlimited length allowed.
2. Numeric datatypes:
   
   1. Integers:
      1. small int (2 bytes)
      2. integer (4 bytes)
      3. big int (8 bytes)
   2. Floating-point numbers:
      1. decimal (variable)
      2. numeric (variable)
      3. real (4 bytes)
      4. double (8 bytes)
3. Boolean:
   1. True
   2. False
   3. Null
4. XML datatype: to store XML data.
5. JSON datatype: to store JSON data.
6. Geometric datatype:
   1. Point
   2. Line
   3. Lseg (finite line segment)
   4. Box
   5. Path
   6. Polygon
   7. Circle
7. Date time datatypes:
   1. Timestamp without timezone
   2. Timestamp with timezone
   3. Date
   4. Time without timezone
   5. Time with timezone
   6. Interval