MySql清除重复数据

### mysql语句

DELETE
FROM `table_name`
WHERE clumn_name IN(SELECT
               clumn_name
             FROM (SELECT
                    clumn_name
                   FROM table_name
                   GROUP BY clumn_name
                   HAVING COUNT(clumn_name) > 1) a)
    AND id NOT IN(SELECT
                    *
                  FROM (SELECT
                          MIN(id)
                        FROM table_name
                        GROUP BY bds_id
                        HAVING COUNT(clumn_name) > 1) b)

 

### 添加唯一索引

alter table tableName add unique(column_name)

### 查看唯一索引

show keys from tableName;

### 删除唯一索引 

drop index Key_name on tableName;

 

uuid 批量插入

UPDATE gfdz_device_signal_definition SET signal_id=REPLACE(UUID(),'-','');
UPDATE gfdz_device_signal_definition SET signal_id = UUID() WHERE signal_id =signal_id;
UPDATE gfdz_device_signal_definition SET signal_id = REPLACE(signal_id,'-','');