SELECT COUNT(*) as cnt FROM (SELECT DISTINCT id, a, b FROM test_distinct) as tmp; 1. 嗯?结果是正确的,那就说明count(distinct expr)生成的查询计划可能和我们想象的不一样,并不是先去重再统计,使用explain分析一下两条语句的查询计划,如下所示: 从表中可以看到,mysql执行引擎直接将count(distinct exp...
select count(*) as cnt from emp; 1. 查询emp表中有佣金的人数: select count(comm) as cnt from emp; 1. 注意,因为count()函数中给出的是comm列,那么只统计comm列非NULL的行数。 查询emp表中月薪大于2500的人数: select count(*) as cnt from emp where sal>2500; 1. 统计月薪与佣金之和大于2500...
select name, count(*) as cnt from subject inner join submission on subject.id=submission.subject_id where submission.create_time=curdate() group by name, submission.subject_id order by cnt desc, submission.subject_id 打卡 不愿透露姓名的神秘牛友 ...
_from = '1' _to = '42' --- I'm doing two SELECT in 1 query. [1] (SELECT *,COUNT(*) as cnt FROM `biz_pm` WHERE _to = 42 GROUP BY t,_from ORDER BY id DESC LIMIT 0,25) UNION ALL [AND 2] (SELECT *,COUNT(*) as cnt FROM `biz_pm` WHERE _from = 42 GROUP BY t...
--常见写法,count distinct写法 SELECT COUNT(DISTINCTcst_id)AScst_cnt FROM@pc_bill_bal WHEREdtBETWEEN'${bizdate-5}'AND'${bizdate}' ; --优化写法 SELECTCOUNT(1)AScst_cnt FROM( SELECT cst_id FROM@pc_bill_bal WHEREdtBETWEEN'${bizdate-5}'AND'${bizdate}' ...
{max_length}s' as table_name,count(1) as cnt from %-${max_length}s union all\n"${table_name}${table_name}doneprintf" select '%-${max_length}s' as table_name,count(1) as cnt\n""invaild_column"printf") t1\n"printf"where table_name <> 'invaild_column'\n"printf"order by ...
SELECT COUNT(*) AS count FROM ( SELECT column FROM table WHERE condition ) AS subquery; 在这个示例中,我们首先在子查询中指定需要查询的列和条件。然后,在外部查询中使用COUNT函数对子查询的结果进行计数,并使用AS关键字给计数结果起一个别名。 这样,我们就可以通过执行这个查询语句来获取子查询的计数...
这里的问题是使sql查询在SQL版本后不检查大小写; VERSION(): 8.0.15 登录用户的Sql查询: SELECT COUNT(*) as cnt FROM accounts WHEREemail = 'AdMin') AND password = '***' AND type IN (1) AND deleted = 0 数据库存储名称=‘admin’ 如何为mysql 8.0设置区分<e 浏览21提问于2019-03-15得票数 ...
select company_id,count(*) as cnt from job_info a join deliver_record b on a.job_id = b.job_id where resume_if_checked = 1 group by company_id ORDER BY company_id 12-16 14:54 牛客运营 假如你从12月开始准备26届校招 2024年12月 - 2025年2月(寒假实习申请)简历撰写:根据个人经历和技...
【主要问题】:从库查询系统表信息与主库不一致,从库COUNT(*)结果与select * 返回条数不同。 -- 主节点 zdhdb=# select count(*) as cnt from pg_partition p, pg_namespace n, pg_class r where p.parentid = r.oid and r.relnamespace = n.oid and r.relname = 'test_table' and n.nspnam...