primary_expression ::= 
   parenthesized_expression |
   constant_expression |
   column_reference |
   variable_reference |
   array_constructor |
   map_constructor |
   case_expression |
   cast_expression |
   extract_expression |
   function_call |
   count_star |
   transform_expression

The following subsections describe each of the primary expressions listed in the above grammar rule, except from count_star, which is the count(*) aggregate function defined in the Using Aggregate Functions section.

To follow along with the examples, create tables and insert the data as described in the Tables Used in the Examples section.