/**
 * postgres-mcp - Statistics Schema Preprocessing
 *
 * Parameter preprocessing / alias normalization functions for stats tools.
 * Handles tableName→table, col→column, schema.table parsing, percentile normalization, etc.
 */
/**
 * Parse schema.table format from table name.
 * Returns { table, schema } with schema extracted from prefix if present.
 * Embedded schema takes priority over explicit schema parameter.
 */
export declare function parseSchemaTable(table: string, explicitSchema?: string): {
    table: string;
    schema: string;
};
/**
 * Valid interval units for time series analysis
 */
export declare const VALID_INTERVALS: readonly ["second", "minute", "hour", "day", "week", "month", "year"];
/**
 * Interval shorthand mappings
 */
export declare const INTERVAL_SHORTHANDS: Record<string, string>;
/**
 * Preprocess basic stats parameters to normalize common input patterns:
 * - tableName → table
 * - col → column
 * - Auto-normalize percentiles from 0-100 to 0-1 format
 * - Replace empty percentiles array with defaults
 */
export declare function preprocessBasicStatsParams(input: unknown): unknown;
/**
 * Preprocess correlation parameters:
 * - tableName → table
 * - col1/col2 → column1/column2
 */
export declare function preprocessCorrelationParams(input: unknown): unknown;
/**
 * Preprocess regression parameters:
 * - tableName → table
 * - x → xColumn
 * - y → yColumn
 * - column1 → xColumn (for consistency with correlation)
 * - column2 → yColumn (for consistency with correlation)
 */
export declare function preprocessRegressionParams(input: unknown): unknown;
/**
 * Preprocess time series parameters:
 * - Extract interval unit from PostgreSQL-style intervals ('1 day' → 'day', '2 hours' → 'hour')
 * - Normalize to lowercase
 * - Handle shorthands: daily→day, hourly→hour, weekly→week, monthly→month
 * - Alias: column → valueColumn, time → timeColumn
 * - Alias: tableName → table
 * - Default interval to 'day' if not provided
 */
export declare function preprocessTimeSeriesParams(input: unknown): unknown;
/**
 * Preprocess hypothesis test parameters:
 * - Normalize testType variants: 'ttest', 't-test', 'T_TEST' → 't_test'
 * - Default testType to 't_test' if not provided
 * - Alias: tableName → table, col → column
 */
export declare function preprocessHypothesisParams(input: unknown): unknown;
/**
 * Preprocess distribution parameters:
 * - Alias: tableName → table, col → column
 */
export declare function preprocessDistributionParams(input: unknown): unknown;
/**
 * Preprocess sampling parameters:
 * - Alias: tableName → table, columns → select
 */
export declare function preprocessSamplingParams(input: unknown): unknown;
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