Python format string sql

For the SQL-formatter to work properly you should meticulously end each of your SQL statements with semicolon (;)

However, we have equiped the sql-formatter with some basic validations:

• Forgotten semicolon validation: The validator will check if the CREATE keyword appears more than twice, indicating the user that he / she may have forgotten a semicolon
• Unbalanced parenthesis: The validator will check if there are unbalanced parenthesis in the query
• Unbalanced case when . end : The validator will check if there are case when statements without end or vice versa

What sql_formatter does not do

This package is just a SQL formatter and therefore

• cannot parse your SQL queries into e.g. dictionaries
• cannot validate your SQL queries to be valid for the corresponding database system / provider

Up to now it only formats queries of the form

Every other SQL commands will remain unformatted, e.g. INSERT INTO .

The main goal of the sql_formatter is to enhance readability and quick understanding of SQL queries via proper formatting. We use indentation and lowercasing / uppercasing as means to arrange statements / clauses and parameters into context. By programmatically standardizing the way to write SQL queries we help the user understand its queries faster.

As a by-product of using the sql_formatter , developer teams can focus on the query logic itself and save time by not incurring into styling decisions, this then begin accomplished by the sql_formatter . This is similar to the goal accomplished by the black package for the Python language, which was also an inspiration for the development of this package for SQL.

We can summarize the main steps of the formatter as follows:

1. Each query is separated from above by two newlines.
2. Everything but main statements* / clauses is lowercased

• CREATE . TABLE / VIEW table_name AS
• SELECT (DISTINCT)
• FROM
• (LEFT / INNER / RIGHT / OUTER) JOIN
• UNION
• ON
• WHERE
• GROUP BY
• ORDER BY
• OVER
• PARTITION BY

1. Indentation is used to put parameters into context. Here an easy example:

SELECT field1, case when field2 > 1 and field2  10 and field1 = 'a' then 1 else 0 end as case_field, . FROM table1 WHERE field1 = 1 and field2  2 or field3 = 5 ORDER BY field1;

This is a very nice, easy example but things can become more complicated if comments come into play

SELECT a.field1, a.field2, b.field3 FROM (SELECT field1, field2 FROM table1 WHERE field1 = 1) as a LEFT JOIN (SELECT field1, field3 FROM table2) as b ON a.field1 = b.field1;

We version our package via semantic versioning, i.e.,

• We use three digits separated by points x1.x2.x3, e.g. 0.5.1
• We increase x1 (the major version) if we introduce breaking changes
  • Exception: Versions with 0 at the beginning (e.g. 0.5.1) mean that the package is not stable yet and therefore every new feature could be a breaking change

  New documentation, refactoring / maintenance of code and admin tasks do not change the versions.

  You can follow the changes introduced by each version in our CHANGELOG

  Thank you very much to Jeremy Howard and all the nbdev team for enabling the fast and delightful development of this library via the nbdev framework.

  For more details on nbdev , see its official tutorial

  Thank you very much for the developers of the black package, which was also an inspiration for the development of this package

  About

  A Python based SQL formatter

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  sqlparse – Parse SQL statements¶

  The sqlparse module provides the following functions on module-level.

  sqlparse. split ( sql, encoding=None ) ¶

  Split sql into single statements.

  Format sql according to options.

  Available options are documented in Formatting of SQL Statements .

  In addition to the formatting options this function accepts the keyword “encoding” which determines the encoding of the statement.

  Returns:	The formatted SQL statement as string.

  sqlparse. parse ( sql, encoding=None ) ¶

  Parse sql and return a list of statements.

  In most cases there’s no need to set the encoding parameter. If encoding is not set, sqlparse assumes that the given SQL statement is encoded either in utf-8 or latin-1.

  Formatting of SQL Statements¶

  The format() function accepts the following keyword arguments.

  keyword_case Changes how keywords are formatted. Allowed values are “upper”, “lower” and “capitalize”. identifier_case Changes how identifiers are formatted. Allowed values are “upper”, “lower”, and “capitalize”. strip_comments If True comments are removed from the statements. truncate_strings If truncate_strings is a positive integer, string literals longer than the given value will be truncated. truncate_char (default: “[…]”) If long string literals are truncated (see above) this value will be append to the truncated string. reindent If True the indentations of the statements are changed. reindent_aligned If True the indentations of the statements are changed, and statements are aligned by keywords. use_space_around_operators If True spaces are used around all operators. indent_tabs If True tabs instead of spaces are used for indentation. indent_width The width of the indentation, defaults to 2. wrap_after The column limit (in characters) for wrapping comma-separated lists. If unspecified, it puts every item in the list on its own line. output_format If given the output is additionally formatted to be used as a variable in a programming language. Allowed values are “python” and “php”. comma_first If True comma-first notation for column names is used.

  © Copyright 2023, Andi Albrecht Revision 2bc8d9c2 .

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