Mini-SQL-Engine

A mini SQL engine to parse and execute simple sql queries implemented in python

Description

• directory contains the database and its schema.
• contains the schema of the database. Each table's schema is given between <begin_table> and <end_table>. The first line is the name of the table and others lines are field(column) names.
• Data stored in each table is given as csv file in directory of the same name as of the table. For example, the data of table 'table1' is given as 'table1.csv'.
• Main source code is in
• Database contains only integer data.
• Queries are entirely case insensitive.
• Only simple queries can be performed. Nested queries are not allowed.
• Error handling is implemented with sufficient error debugging details.

Run Query

Inside directory, run python mini_sql.py "<sql_query>"

Valid queries

• Normal select queries
  • select * from table1
  • select a, b from table1
• Aggregate functions like min, max, avg, sum, count
  • select max(a), min(b) from table1
• Select distinct values of a column
  • select distinct(a) from table1
• Conditional select with at most two conditions joined by and or or
  • select a from table1 where a = 10
  • select a, b from table1 where a = c or b = 5
• Table join and aliasing
  • select * from table1, table2
  • select a, t1.b, c, t2.d from table1 as t1, table2 as t2 where t1.b = t2.b and t2.d >= 0