Mysql练习

统计重复数据：

SELECT COUNT(*) as repeat_count, t.txt
FROM
    index_shenhf_copy t
GROUP BY
    t.txt
HAVING
    repeat_count > 1;

过滤重复数据方式1：

SELECT
    DISTINCT t.txt
FROM
    index_shenhf_copy t;

 

 

过滤重复数据方式2

SELECT
    t.txt,t.id
FROM
    index_shenhf_copy t
GROUP BY
    t.txt,t.id;

过滤创建新表

CREATE TABLE tmp SELECT
    t.txt,t.time
FROM
    index_shenhf_copy t
GROUP BY
    t.txt;

 

CREATE TABLE newtmp LIKE index_shenhf; 复制表结构