The Web System processes information and manages data with the support of SQL, the most widely used relational database computer language. SQL stands for Structured Query Language and manages data in relational databases: sets of related information stored in tables.
SQL performs operations on tables as a whole (creation, deletion, editing), and on the data within a table (sampling, editing, adding, and deleting). Full SQL documentation is available at http://www.postgresql.org/docs/current/static/sql-commands.html
To ease the process of working with SQL, Yonicycle developed a query generator named the Query Builder. A Query is a command that a user gives to a database in order to get desired result in the form of a table or a single value. The Query Builder has a visually intuitive interface and will help you to create queries of varying complexity for users with only basic knowledge and little or no experience with SQL.
The Query Builder's Tabs walk the user through a multi step process and automatically generates SQL. Advanced users can go directly to the SQL tab and manually enter a query. The Query Builder checks for errors and in case of a mistake, a message is displayed.
Note: Combining queries:
query1 UNION [ALL] query2 query1 INTERSECT [ALL] query2 query1 EXCEPT [ALL] query2 must be done by typing in the SQL Tab. There is no specific GUI for this functionality within the Query Builder.