/**
 * SQL Mode 2 — SELECT Translator
 *
 * Translates SELECT/FROM/WHERE/ORDER BY/LIMIT/OFFSET/DISTINCT/aliases/IS NULL
 * into MongoDB aggregate pipeline stages.
 */
export declare function translateWhere(where: unknown): Record<string, unknown>;
export declare function translateColumns(columns: unknown, tableAliases: Map<string, string>): Record<string, unknown> | null;
export interface OrderByResult {
    sort: Record<string, 1 | -1>;
    /** Computed fields that need $addFields before the $sort */
    computedFields?: Record<string, unknown>;
}
export declare function translateOrderBy(orderBy: unknown, tableAliases: Map<string, string>): OrderByResult | null;
export declare function translateLimit(limit: unknown): {
    limit?: number;
    skip?: number;
};
export declare function translateDistinct(columns: unknown, tableAliases: Map<string, string>): Record<string, unknown>[] | null;
export declare function likeToRegex(pattern: string): string;
/**
 * Convert an AST node to a MongoDB aggregation expression.
 * Used for complex expressions in WHERE ($expr), ORDER BY, and GROUP BY.
 */
export declare function astToMongoAggExpr(node: Record<string, unknown>): unknown;
export declare function extractFieldName(node: Record<string, unknown>): string;
export declare function extractValue(node: Record<string, unknown>): unknown;
export declare function extractInList(node: Record<string, unknown>): unknown[];
export declare function resolveColumnRef(expr: Record<string, unknown>, tableAliases: Map<string, string>): string;
export declare function buildTableAliases(from: unknown): Map<string, string>;
/**
 * Build the full aggregate pipeline stages from a SELECT AST.
 */
export declare function buildSelectPipeline(ast: Record<string, unknown>): Record<string, unknown>[];
/**
 * Extract collection name from AST FROM clause.
 * For derived tables (subquery in FROM), returns the inner subquery's collection.
 */
export declare function extractCollection(ast: Record<string, unknown>): string;
/**
 * Check if the FROM clause contains a derived table (subquery in FROM).
 * Returns the derived table info if found.
 */
export declare function extractDerivedTable(from: unknown): {
    subAst: Record<string, unknown>;
    alias: string;
} | null;
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