PostgreSQL/Constraints/Check

Specifying three check constaints to a table

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postgres=# postgres=# CREATE TABLE products ( postgres(# product_no integer, postgres(# price numeric, CHECK (price > 0), postgres(# discounted_price numeric, postgres(# CHECK (discounted_price > 0), postgres(# CHECK (price > discounted_price) postgres(# ); CREATE TABLE postgres=# postgres=# drop table products; DROP TABLE postgres=# postgres=# postgres=#

      </source>
   
  

Use boolean operator in check statement

   <source lang="sql">

postgres=# postgres=# postgres=# CREATE TABLE products ( postgres(# product_no integer, postgres(# name text, postgres(# price numeric CHECK (price > 0), postgres(# discounted_price numeric, postgres(# CHECK (discounted_price > 0 AND price > discounted_price) postgres(# ); CREATE TABLE postgres=# drop table products; DROP TABLE postgres=# postgres=#

      </source>