PGPLSQL比较2个日期

Question

你有这样的代码，IF附近有语法错误。任何人都可以睁开眼睛看我错在哪里？

CREATE OR REPLACE FUNCTION accruals_daily_posting_func() 
    RETURNS VARCHAR AS $$ 
BEGIN

    DROP TABLE IF EXISTS t;
    CREATE TEMPORARY TABLE t as ( SELECT sum( actual_trade_spend ) AS sum_ad FROM accruals_detailed );
IF CURRENT_DATE > ( SELECT max( posting_date ) FROM accruals_daily_posting ) THEN
    BEGIN
    INSERT INTO accruals_daily_posting VALUES
        (
        now()::date AS posting_date,
        ( SELECT sum_ad FROM t ) AS total_trade_spend_in_the_system,
        ( SELECT sum_ad - ( SELECT total_trade_spend_in_the_system FROM accruals_daily_posting 
                                                                            WHERE posting_date = ( SELECT max( posting_date ) FROM accruals_daily_posting ) 
        ) FROM t ) AS change_in_total_trade_spend_in_the_system_since_previous_date,
        TIMESTAMP AS created_at,
        TIMESTAMP AS updated_at
        );
    RETURN 'Successfully done';
    END IF;
END;
$$ LANGUAGE plpgsql;