dt-sql-parser

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dt-sql-parser is a SQL Parser project built with ANTLR4, and it's mainly for the BigData field. The ANTLR4 generated the basic Parser, Visitor, and Listener, so it's easy to complete the syntax validation, tokenizer, traverse the AST, and so on features.

Additionally, it provides auxiliary functions such as SQL splitting and code completion.

Supported SQL:

• MySQL
• Flink SQL
• Spark SQL
• Hive SQL
• PostgreSQL
• Trino SQL
• Impala SQL

Supported auxiliary methods

SQL Type	SQL Spliting	Code Completion
MySQL	✅	✅
Flink SQL	✅	✅
Spark SQL	✅	✅
Hive SQL	✅	✅
PostgreSQL	✅	✅
Trino SQL	✅	✅
Impala SQL	✅	✅

Tips: This project is the default for Javascript language, also you can try to compile it to other languages if you need.

Integrating SQL Parser with Monaco Editor

We have provided monaco-sql-languages, it is easily to integrate with monaco-editor.

Tips: If you want to run dt-sql-parser in browser, don't forget to install the assert and util polyfills, and define the global variable process.env. None of this is needed in the node environment, because node has them built-in.

Installation

# use npm
npm i dt-sql-parser --save

# use yarn
yarn add dt-sql-parser

Usage

We recommend learning the Fundamentals usage before continuing. The dt-sql-parser library provides SQL Parser classes for different types of SQL.

import { MySQL, FlinkSQL, SparkSQL, HiveSQL, PostgresSQL, TrinoSQL, ImpalaSQL } from 'dt-sql-parser';

Before using syntax validation, code completion, and other features, it is necessary to instantiate the Parser of the relevant SQL type. For instance, one can consider using MySQL as an example:

const parser = new MySQL();

The following usage examples will utilize the MySQL, and the Parser for other SQL types will be used in a similar manner as MySQL.

Syntax Validation

import { MySQL } from 'dt-sql-parser';

const parser = new MySQL();

const correctSql = 'select id,name from user1;';
const errors = parser.validate(correctSql);
console.log(errors); 

output:

/* 
[]
*/

Validate failed:

const incorrectSql = 'selec id,name from user1;'
const errors = parser.validate(incorrectSql);
console.log(errors); 

output:

/*
[
  {
    endCol: 5,
    endLine: 1,
    startCol: 0,
    startLine: 1,
    message: "mismatched input 'SELEC' expecting {<EOF>, 'ALTER', 'ANALYZE', 'CALL', 'CHANGE', 'CHECK', 'CREATE', 'DELETE', 'DESC', 'DESCRIBE', 'DROP', 'EXPLAIN', 'GET', 'GRANT', 'INSERT', 'KILL', 'LOAD', 'LOCK', 'OPTIMIZE', 'PURGE', 'RELEASE', 'RENAME', 'REPLACE', 'RESIGNAL', 'REVOKE', 'SELECT', 'SET', 'SHOW', 'SIGNAL', 'UNLOCK', 'UPDATE', 'USE', 'BEGIN', 'BINLOG', 'CACHE', 'CHECKSUM', 'COMMIT', 'DEALLOCATE', 'DO', 'FLUSH', 'HANDLER', 'HELP', 'INSTALL', 'PREPARE', 'REPAIR', 'RESET', 'ROLLBACK', 'SAVEPOINT', 'START', 'STOP', 'TRUNCATE', 'UNINSTALL', 'XA', 'EXECUTE', 'SHUTDOWN', '--', '(', ';'}"
  }
]
*/

We instanced a Parser object, and use the validate method to check the SQL syntax, if failed returns an array object includes error message.

Tokenizer

Get all tokens by the Parser:

import { MySQL } from 'dt-sql-parser';

const parser = new MySQL()
const sql = 'select id,name,sex from user1;'
const tokens = parser.getAllTokens(sql)
console.log(tokens)

output:

/*
[
  {
    channel: 0
    column: 0
    line: 1
    source: [SqlLexer, InputStream]
    start: 0
    stop: 5
    tokenIndex: -1
    type: 137
    _text: null
  },
  ...
]
*/

Visitor

Traverse the tree node by the Visitor:

import { MySQL, AbstractParseTreeVisitor } from 'dt-sql-parser';
import type { MySqlParserVisitor } from 'dt-sql-parser';

const parser = new MySQL();
const sql = `select id,name from user1;`;
const tree = parser.parse(sql);

type Result = string;

class MyVisitor extends AbstractParseTreeVisitor<Result> implements MySqlParserVisitor<Result> {
    protected defaultResult() {
        return '';
    }
    visitTableName(ctx) {
        let tableName = ctx.text.toLowerCase();
        console.log('TableName:', tableName);
        return '';
    }
    visitSelectElements(ctx) {
        let selectElements = ctx.text.toLowerCase();
        console.log('SelectElements:', selectElements);
        return '';
    }
    visitProgram(ctx) { // program is root rule
        this.visitChildren(ctx);
        return 'Return by program context'
    }
}
const visitor = new MyVisitor();
const result = visitor.visit(tree);

console.log(result);

output:

/*
SelectElements: id,name
TableName: user1
*/
/*
Return by program node
*/

Tips: The node's method name can be found in the Visitor file under the corresponding SQL directory

Listener

Access the specified node in the AST by the Listener

import { MySQL } from 'dt-sql-parser';
import type { MySqlParserListener } from 'dt-sql-parser';

const parser = new MySQL();
const sql = 'select id,name from user1;';
const parseTree = parser.parse(sql);

class MyListener implements MySqlParserListener {
    enterTableName(ctx) {
        let tableName = ctx.text.toLowerCase();
        console.log('TableName:', tableName);
    }
    enterSelectElements(ctx) {
        let selectElements = ctx.text.toLowerCase();
        console.log('SelectElements:', selectElements);
    }
}
const listenTableName = new MyListener();
parser.listen(listenTableName as MySqlParserListener, parseTree);

output:

/*
SelectElements: id,name
TableName: user1
*/

Tips: The node's method name can be found in the Listener file under the corresponding SQL directory

Splitting SQL statements

Take FlinkSQL as an example:

import { FlinkSQL } from 'dt-sql-parser';
const parser = new FlinkSQL();
const sql = 'SHOW TABLES;\nSELECT * FROM tb;';
const sqlSlices = parser.splitSQLByStatement(sql);
console.log(sqlSlices)

output:

/*
[
  {
    startIndex: 0,
    endIndex: 11,
    startLine: 1,
    endLine: 1,
    startColumn: 1,
    endColumn: 12,
    text: 'SHOW TABLES;'
  },
  {
    startIndex: 13,
    endIndex: 29,
    startLine: 2,
    endLine: 2,
    startColumn: 1,
    endColumn: 17,
    text: 'SELECT * FROM tb;'
  }
]
*/

Code Completion

Obtaining code completion information at a specified position in SQL. We can refer to the example of using FlinkSQL.

Invoke the getSuggestionAtCaretPosition method, pass the SQL content and the row and column numbers indicating the position where code completion is desired.

• keyword candidates list

  import { FlinkSQL } from 'dt-sql-parser';
  const parser = new FlinkSQL();
  const sql = 'CREATE ';
  const pos = { lineNumber: 1, column: 16 }; // the end position
  const keywords = parser.getSuggestionAtCaretPosition(sql, pos)?.keywords;
  console.log(keywords);
  

  output:

  /*
  [ 'CATALOG', 'FUNCTION', 'TEMPORARY', 'VIEW', 'DATABASE', 'TABLE' ] 
  */
  

• Obtaining information related to grammar completion

  const parser = new FlinkSQL();
  const sql = 'SELECT * FROM tb';
  const pos = { lineNumber: 1, column: 16 }; // after 'tb'
  const syntaxSuggestions = parser.getSuggestionAtCaretPosition(sql, pos)?.syntax;
  console.log(syntaxSuggestions);
  

  output:

  /*
  [
    {
      syntaxContextType: 'table',
      wordRanges: [
        {
          text: 'tb',
          startIndex: 14,
          stopIndex: 15,
          line: 1,
          startColumn: 15,
          stopColumn: 16
        }
      ]
    },
    {
      syntaxContextType: 'view',
      wordRanges: [
        {
          text: 'tb',
          startIndex: 14,
          stopIndex: 15,
          line: 1,
          startColumn: 15,
          stopColumn: 16
        }
      ]
    }
  ]
  */
  

The grammar-related code completion information returns an array, where each item represents what grammar can be filled in at that position. For example, the output in the above example represents that the position can be filled with either a table name or a view name. In this case, syntaxContextType represents the type of grammar that can be completed, and wordRanges represents the content that has already been filled.

Other API

• createLexer Create an instance of Antlr4 Lexer and return it;
• createParser Create an instance of Antlr4 parser and return it;
• parse Parses the input SQL and returns the parse tree;

License

MIT