1.查询重复值: select code,count(*) as count from hospital group by code having count>1; 该语句查询code重复值大于1的记录 2.删除重复: DELETE FROM hospital WHERE id NOT IN (SELECT dt.minno FROM (SELECT MIN(id) AS minno FROM hospital GROUP BY code) dt); 该语句保留id最小的记录,其余code重复的
1 查询重复值 ); 2 删除重复值 -- 创建临时表 ) ); -- 把重复数据放进临时表 INSERT Hb_Student_a SELECT id,studentNumber FROM Hb_Student ) ); -- 删除重复数据 DELETE a FROM Hb_Student AS a JOIN Hb_Student_a AS b ON a.id=b.id WHERE a.id=b.id ;
Given an array of integers, find out whether there are two distinct indices i and j in the array such that the difference between nums[i] and nums[j] is at most t and the difference between i and j is at most k. 这道题跟之前两道Contains Duplicate 包含重复值和Conta
Given an array of integers and an integer k, return true if and only if there are two distinct indices i and j in the array such that nums[i] = nums[j] and the difference between i and j is at most k. (Old Version) Given an array of integers and an i
Given an array of integers, find if the array contains any duplicates. Your function should return true if any value appears at least twice in the array, and it should return false if every element is distinct. 这道题不算难题,就是使用一个哈希表,遍历整个数组,如果哈希表里存在,返回fal
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