题解 | #计算25岁以上和以下的用户数量#
计算25岁以上和以下的用户数量
https://www.nowcoder.com/practice/30f9f470390a4a8a8dd3b8e1f8c7a9fa
SELECT IF(IFNULL(age, 0) < 25, '25岁以下', '25岁及以上') AS age_cut, COUNT(*) AS number FROM user_profile GROUP BY age_cut;
条件函数IF的使用
计算25岁以上和以下的用户数量
https://www.nowcoder.com/practice/30f9f470390a4a8a8dd3b8e1f8c7a9fa
SELECT IF(IFNULL(age, 0) < 25, '25岁以下', '25岁及以上') AS age_cut, COUNT(*) AS number FROM user_profile GROUP BY age_cut;
条件函数IF的使用
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球球与墩墩:这不是前端常考的对象扁平化吗,面试官像是前端出来的
const flattern = (obj) => {
const res = {};
const dfs = (curr, path) => {
if(typeof curr === 'object' && curr !== null) {
const isArray = Array.isArray(curr);
for(let key in curr) {
const newPath = path ? isArray ? `${path}[${key}]` : `${path}.${key}` : key;
dfs(curr[key], newPath);
}
} else {
res[path] = curr
}
}
dfs(obj);
return res;
}
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