pandas-query-sql 0.8.1
sqldf for pandas
License: MIT
Requires Python: >=3.8

pandasql
========

This is a fork of the original `pandasql`, with support of multiple SQL
backends and more convenient interface. See below for more info.

`pandasql` allows you to query `pandas` DataFrames using SQL syntax. It works 
similarly to `sqldf` in R. `pandasql` seeks to provide a more familiar way of 
manipulating and cleaning data for people new to Python or `pandas`.

## Installation
```
$ pip install -U pandasql
```

## Basics
In addition to the original pandasql's ``sqldf`` function this fork has
a class ``PandaSQL``, which new users are encouraged to use.

`PandaSQL` Class
---
The class is more convenient when you need to perform multiple queries. `PandaSQL` takes 2 arguments:
   - `db_uri`: an optional SQLAlchemy connection string (defaults to in-memory SQLite database)
   - `persist`: an optional boolean to determine if loaded tables are persisted in the database (holds connection open, default False)

`sqldf` Function
---
The main function used in pandasql is `sqldf`. `sqldf` accepts 3 parameters:
   - an sql query string
   - an optional SQLAlchemy connection string (defaults to in-memory SQLite database)
   - an optional dict of session/environment variables (defaults to `**locals()`,`**globals()`)


## Querying
`pandasql` uses [SQLite syntax](http://www.sqlite.org/lang.html). Any `pandas` 
dataframes will be automatically detected by `pandasql`. You can query them as 
you would any regular SQL table.


```
$ python
>>> from pandasql import PandaSQL, load_meat, load_birth
>>> meat = load_meat()
>>> births = load_births()
>>> pdsql = PandaSQL()
>>> print pysqldf("SELECT * FROM meat LIMIT 10;").head()
                  date  beef  veal  pork  lamb_and_mutton broilers other_chicken turkey
0  1944-01-01 00:00:00   751    85  1280               89     None          None   None
1  1944-02-01 00:00:00   713    77  1169               72     None          None   None
2  1944-03-01 00:00:00   741    90  1128               75     None          None   None
3  1944-04-01 00:00:00   650    89   978               66     None          None   None
4  1944-05-01 00:00:00   681   106  1029               78     None          None   None
```

joins and aggregations are also supported
```
>>> q = """SELECT
        m.date, m.beef, b.births
     FROM
        meats m
     INNER JOIN
        births b
           ON m.date = b.date;"""
>>> joined = pyqldf(q)
>>> print joined.head()
                    date    beef  births
403  2012-07-01 00:00:00  2200.8  368450
404  2012-08-01 00:00:00  2367.5  359554
405  2012-09-01 00:00:00  2016.0  361922
406  2012-10-01 00:00:00  2343.7  347625
407  2012-11-01 00:00:00  2206.6  320195

>>> q = "select
           strftime('%Y', date) as year
           , SUM(beef) as beef_total
           FROM
              meat
           GROUP BY
              year;"
>>> print pysqldf(q).head()
   year  beef_total
0  1944        8801
1  1945        9936
2  1946        9010
3  1947       10096
4  1948        8766
```
---
## More Info
More information and code samples available in the [examples](https://github.com/bluestealth/pandasql/blob/master/examples/demo.py) folder.