# Class: WithClauseParser

Defined in: packages/core/src/parsers/WithClauseParser.ts:22

Parser for SQL WITH clauses (Common Table Expressions - CTEs). Parses only the WITH clause portion of SQL, not the entire query.

Note: For most use cases, use SelectQueryParser which provides more comprehensive SQL parsing. This parser should only be used for the special case where you need to analyze only the WITH clause portion.

Example

// Parses only the WITH clause, not the following SELECT
const sql = "WITH recursive_cte AS (SELECT 1 as n UNION SELECT n+1 FROM recursive_cte WHERE n < 10)";
const withClause = WithClauseParser.parse(sql);
console.log(withClause.recursive); // true
console.log(withClause.tables.length); // 1

Constructors

Constructor

new WithClauseParser(): WithClauseParser

Returns

WithClauseParser

Methods

parse()

static parse(query): WithClause

Defined in: packages/core/src/parsers/WithClauseParser.ts:41

Parses a SQL string containing only a WITH clause into a WithClause AST. The input should contain only the WITH clause, not the subsequent main query.

Parameters

query

string

The SQL string containing only the WITH clause

Returns

WithClause

The parsed WithClause object

Throws

Error if the syntax is invalid or there are unexpected tokens after the WITH clause

Example

// Correct: Only the WITH clause
const sql = "WITH users_data AS (SELECT id, name FROM users)";
const withClause = WithClauseParser.parse(sql);

// Error: Contains SELECT after WITH clause
// const badSql = "WITH users_data AS (SELECT id, name FROM users) SELECT * FROM users_data";

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parseFromLexeme()

static parseFromLexeme(lexemes, index): object

Defined in: packages/core/src/parsers/WithClauseParser.ts:73

Parses a WITH clause from an array of lexemes starting at the specified index.

Parameters

lexemes

Lexeme[]

Array of lexemes to parse from

index

number

Starting index in the lexemes array

Returns

object

Object containing the parsed WithClause and the new index position

value

value: WithClause

newIndex

newIndex: number

headerComments

headerComments: null | string[]

Throws

Error if the syntax is invalid or WITH keyword is not found

Example

const tokenizer = new SqlTokenizer("WITH cte AS (SELECT 1)");
const lexemes = tokenizer.readLexmes();
const result = WithClauseParser.parseFromLexeme(lexemes, 0);
console.log(result.value.tables.length); // 1
console.log(result.newIndex); // position after the WITH clause