https://github.com/akshayxml/mini-sql-engine

A mini sql engine which can run a subset of SQL queries using command line interface.
https://github.com/akshayxml/mini-sql-engine

database mini-sql-engine sql-queries

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A mini sql engine which can run a subset of SQL queries using command line interface.

• Host: GitHub
• URL: https://github.com/akshayxml/mini-sql-engine
• Owner: akshayxml
• Created: 2021-01-24T09:36:15.000Z (almost 5 years ago)
• Default Branch: main
• Last Pushed: 2021-01-24T09:40:59.000Z (almost 5 years ago)
• Last Synced: 2025-01-25T04:09:48.133Z (11 months ago)
• Topics: database, mini-sql-engine, sql-queries
• Language: Python
• Homepage:
• Size: 11.7 KB
• Stars: 1
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: readme.md

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README

          
# Mini SQL Engine

A mini sql engine which can run a subset of SQL queries using command line interface.

## Dataset:

1. csv files for tables.

   - If a file is : File1.csv , the table name should be File1

   - There should be no tab separation or space separation, but the values can be in double quotes or without quotes.

2. All the elements in files should be integers.

3. A file named: metadata.txt should be given which will have the following structure for each table:

   ```

    

    

    ..

    ..

    

    

4. Column names should be unique among all the tables. So column names should not​ preceded by table names in SQL queries.

## Type of Queries

The the following set of queries are supported:

1. Project​ Columns(could be any number of columns) from one or more tables :

   - `Select * from table_name`;

   - `Select col1, col2 from table_name`;

2. Aggregate functions​: Simple aggregate functions on a single column. Sum, average, max, min and count. 

    - `Select max(col1) from table_name`;

3. Select/project with ​distinct​ from one table: (distinct of a pair of values indicates the pair should be distinct) 

    - `Select distinct col1, col2 from table_name;`

4. Select with ​WHERE​ from one or more tables :

    - `Select col1,col2 from table1,table2 where col1 = 10 AND col2 = 20;`

    - In the where queries, there should be a maximum of one AND/ORoperator with no NOT operators.

    - Relational operators that are to be handled in the assignment, the operators include "< , >, <=, >=, =".

5.  Select/Project Columns(could be any number of columns) from table using “​group by​”:  

    - `Select col1, COUNT(col2) from table_name group by col1.`

    - In the group by queries, Sum/Average/Max/Min/Count can be used as aggregate functions.

6. Select/Project Columns(could be any number of columns) from table in ascending/descending order according to a column using “​order by”​:

    - `Select col1,col2 from table_name order by col1 ASC|DESC`.

    - At max only one column can be used to sort the rows.

    - Query can have multiple tables

## Format of Input :

`python3 sql_engine.py ""`

## Format of Output  :

    

                        Row 1 

                        Row 2 

                        ....... 

                        Row N