Class SQLRowLimiter

src/utils/sql-row-limiter.ts:6–155

 * Shared utility for applying row limits to SELECT queries only using database-native LIMIT clauses
 */
export class SQLRowLimiter {
  /**
   * Check if a SQL statement is a SELECT query that can benefit from row limiting
   * Only handles SELECT queries
   */
  static isSelectQuery(sql: string): boolean {
    const trimmed = sql.trim().toLowerCase();
    return trimmed.startsWith('select');
  }

  /**
   * Check if a SQL statement already has a LIMIT clause.
   * Strips comments and string literals first to avoid false positives.
   */
  static hasLimitClause(sql: string): boolean {
    // Strip comments and strings to avoid matching LIMIT inside them
    const cleanedSQL = stripCommentsAndStrings(sql);
    // Detect LIMIT clause - handles literal numbers and parameter placeholders ($1, ?, @p1)
    const limitRegex = /\blimit\s+(?:\d+|\$\d+|\?|@p\d+)/i;
    return limitRegex.test(cleanedSQL);
  }

  /**
   * Check if a SQL statement already has a TOP clause (SQL Server).
   * Strips comments and string literals first to avoid false positives.
   */
  static hasTopClause(sql: string): boolean {
    // Strip comments and strings to avoid matching TOP inside them
    const cleanedSQL = stripCommentsAndStrings(sql);
    // Simple regex to detect TOP clause - handles most common cases
    const topRegex = /\bselect\s+top\s+\d+/i;
    return topRegex.test(cleanedSQL);
  }

  /**
   * Extract existing LIMIT value from SQL if present.
   * Strips comments and string literals first to avoid false positives.
   */
  static extractLimitValue(sql: string): number | null {
    // Strip comments and strings to avoid matching LIMIT inside them
    const cleanedSQL = stripCommentsAndStrings(sql);
    const limitMatch = cleanedSQL.match(/\blimit\s+(\d+)/i);
    if (limitMatch) {
      return parseInt(limitMatch[1], 10);
    }
    return null;
  }

  /**
   * Extract existing TOP value from SQL if present (SQL Server).
   * Strips comments and string literals first to avoid false positives.
   */
  static extractTopValue(sql: string): number | null {
    // Strip comments and strings to avoid matching TOP inside them
    const cleanedSQL = stripCommentsAndStrings(sql);
    const topMatch = cleanedSQL.match(/\bselect\s+top\s+(\d+)/i);
    if (topMatch) {
      return parseInt(topMatch[1], 10);