Crate sql_select_parser

Crate sql_select_parser 

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§sql_select_parser

Link to crates.io

§Overview

sql_select_parser is a CLI tool for parsing SQL SELECT queries into a structured Abstract Syntax Tree (AST) using Rust and pest. Ideal for developers and DB admins, this tool helps validate and analyze SQL queries programmatically.

§Features

  • SQL Parsing: Parses SELECT queries with various clauses and functions.
  • AST Generation: Transforms SQL into an AST for analysis and manipulation.
  • CLI Interface: Built with clap for easy command-line use.
  • Makefile: Automates tasks like building, testing, and formatting.
  • Detailed Error Handling: Identifies SQL syntax issues with clear error messages.

§Grammar Explanation

This grammar defines the syntax rules for a simple SQL parser that supports basic SELECT queries with columns, tables, conditions, and functions.

  • WHITESPACE: Matches spaces, tabs, newlines, and carriage returns. Ignored during parsing.

  • Keywords:

    • SELECT, FROM, WHERE: Matches SQL keywords to define different clauses.

  • identifier: Matches valid SQL identifiers, which start with a letter or underscore and can contain alphanumeric characters or underscores.

  • number: Matches integers, optionally with a negative sign.

  • string: Matches single-quoted text strings.

  • boolean: Matches boolean values (true or false).

  • operator: Matches common comparison operators (!=, >=, <=, <, >, =).

  • function_name: Matches function names, which start with a letter or underscore and can contain alphanumeric characters or underscores.

  • table: Matches a table, which can be a simple identifier or a nested SELECT query as a subquery.

  • select_query: Defines the structure of a SELECT query, which includes:

    • A SELECT keyword followed by a list of selected items (select_list).
    • A FROM clause specifying the table.
    • An optional WHERE clause with conditions.

  • select_list: Matches a list of items (columns or functions) to be selected, separated by commas.

  • star: Matches the * character to select all columns.

  • select_item: Represents an item in the SELECT clause, which can be a function call, identifier (column), or *.

  • function_call: Matches a function call, allowing functions with arguments.

  • where_clause: Matches a WHERE clause that contains conditions.

  • condition: Represents a condition in the WHERE clause, using an identifier, operator, and value for comparison.

  • value: Represents the values used in conditions, which can be a string, number, or boolean.

Structs§

Condition
A condition for where. Contains the column name, comparison operator, and the value to compare.
SQLParser
Main module that contains rules for parser
SelectQuery
Main structure for storing a SQL select query. Contains selected columns, the table, and an optional WHERE filter.

Enums§

ParseError
Possible errors when parsing an SQL query.
Rule
SelectItem
Types of items in select: a simple column, a function, or a star (*).
Table
The table for select, which can be a simple table or a subquery.
Value
Possible values for SQL expressions.

Functions§

parse_query
Function to parse an SQL query. Takes an SQL query as text and returns a SelectQuery or an error.