- Structured query language (SQL) is a programming language designed for getting information from and updating a database. They are used for managing data in relational database management system (RDBMS). Queries take the form of a command language that lets you select, insert, update, find out the location of data, and so forth. There is also a programming interface.
- The UPDATE query is used to update existing records in a table. The SELECT query is used to select data from a database. The result is stored in a result table, called the result-set.
- We use PROC SQL within SAS, sqldf from within R and pandasql from within Python for using SQL sytax. SHOW EXAMPLES
SQLAlchemy Library: This allows you to execute raw SQL queries on tables in database present in MySQL-server from python. These also exists SQLAlchemy Expression Language which represents relational database structures and expressions using Python constructs. The expression language improves the maintainability of the code by hiding the SQL language and thus disallowing a mix of Python code and SQL code.
from sqlalchemy import text
with engine.connect() as con:
rs = con.execute(text(‘SELECT * FROM BigDiamonds limit 1’))
[u’Unnamed’, u’carat’, u’cut’, u’color’, u’clarity’, u’tabl’, u’depth’, u’cert’, u’measurements’, u’price’, u’x’, u’y’, u’z’] [(1L, 0.25, ‘V.Good’, ‘K’, ‘I1’, 59.0, 63.7, ‘GIA’, ‘3.96 x 3.95 x 2.52’, 0.0, 3.96, 3.95, 2.52)]