/**
 * SQL Dialect abstraction for cross-database semantic query generation.
 *
 * Each database has different syntax for date truncation, identifier quoting,
 * type casting, etc. This module provides a uniform interface so that
 * SemanticLayer.composeQuery() generates portable SQL.
 */
export interface SQLDialect {
    /** Driver name(s) this dialect covers. */
    readonly name: string;
    /** Truncate a date/timestamp column to a given granularity. */
    dateTrunc(granularity: string, columnSql: string): string;
    /** Quote an identifier (table/column name). */
    quoteIdentifier(name: string): string;
    /** CURRENT_TIMESTAMP expression. */
    currentTimestamp(): string;
    /** Cast an expression to DATE type. */
    castToDate(expr: string): string;
    /** LIMIT N clause (some dialects use TOP N instead). */
    limitClause(n: number): string;
    /** Whether LIMIT goes at the end (true) or must use TOP (false). */
    readonly limitAtEnd: boolean;
    /** String concatenation for two expressions. */
    concat(a: string, b: string): string;
    /** ILIKE or case-insensitive LIKE equivalent. */
    ilike(column: string, pattern: string): string;
}
/**
 * Get the SQL dialect for a given driver name.
 * Falls back to DuckDB dialect if the driver is unknown.
 */
export declare function getDialect(driver?: string): SQLDialect;
/**
 * List all supported dialect driver names.
 */
export declare function listDialectDrivers(): string[];
/**
 * A concise, human-readable SQL-conventions block for the generation prompt, so
 * the model writes dialect-correct SQL (quoting, row-limiting, date functions)
 * instead of a DuckDB/Postgres default that then fails on Snowflake/BigQuery/etc.
 * Every example is derived from the real dialect object, so it can never drift
 * from what the semantic composer emits.
 */
export declare function describeDialectForPrompt(driver?: string): string;
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