pg select中使用变量

DO $$
DECLARE myvar int8;
BEGIN
    --SELECT 168038292783239160 INTO myvar;
    myvar=168038292783239168;
    DROP TABLE IF EXISTS tmp_table;
    CREATE TABLE tmp_table AS
    select * from ess_storehouseini es where s_storages_id= myvar;
END $$;

SELECT * FROM tmp_table;