count_distinct3.result

这是linux下运行的mysql软件包,可用于linux 下安装 php + mysql + apach 的网络配置

DROP TABLE IF EXISTS t1, t2;
CREATE TABLE t1 (id INTEGER, grp TINYINT, id_rev INTEGER);
SELECT COUNT(*) FROM t1;
COUNT(*)
4181000
SELECT COUNT(DISTINCT id) FROM t1 GROUP BY grp;
DROP TABLE t1;
set @@read_buffer_size=default;