case when <判断表达式> then <表达式> when <判断表达式> then <表达式> when <判断表达式> then <表达式> …… else<表达式> end 1. 2. 3. 4. 5. 6. 四,练习题 1.查询所有学生的学号,姓名,选课数,总成绩 select score.学号,student.姓名,count(score.课程号) as 选课数,sum(score.成绩) as 总...
(SELECT count(*) from W3S19 b WHERE a.aid=b.aid) as num, (SELECT count(*) FROM W3S19 c WHERE a.aid=c.aid AND H110 IS NULL AND H112 IS NULL) as num_null, (SELECT count(*) FROM W3S19 d WHERE a.aid=d.aid AND (H110=1 or H112=1)) AS num_yes FROM W3 a 所以这需要逐步...
CASE的简单函数使用简便,但无法应对较为复杂的场景,这就需要用到条件表达式了,其语法结构如下: CASE WHEN condition THEN result1 ELSE result2 END 1. 2. 3. 解释一下,语句中的condition是条件判断,如果该判断结果为true,那么CASE语句将返回result,否则返回result2,如果没有ELSE,则返回null。CASE与END之间可以有...
这里的问题是,我不确定条件和IF/ELSE语句是如何在sqlite中工作的。我不相信使用CASE/WHEN/THEN语句会对我有帮助。 VALUES (001,1) 使用上面的代码,我会在查询语句 浏览0提问于2019-09-17得票数 0 回答已采纳 1回答 从System.Data.SQLite.SQLiteException获取更多信息 、、 当System.Data.SQLite遇到SQL语法错误时...
-- 数据的聚合与分类(通过GROUP BY实现) SELECT CASE WHEN age < 30 THEN 'Young' WHEN age >= 30 AND age < 40 THEN 'Middle-aged' ELSE 'Senior' END AS age_group, COUNT(*) AS count FROM basic_table GROUP BY age_group; 数据的分区与汇总 代码语言:javascript 复制 -- 数据的分区与汇总(通...
select max(continuousDays)-1from (select count(*) continuousDaysfrom (select sum(changeSign) over(order by tradeDate) unRiseDaysfrom (select tradeDate,case when price>lag(price) over(order by tradeDate) then 0 else 1 end changeSign from AAPL) )group by unRiseDays)这也不单是 SQLite 的...
groupBy (testresult^.TestResultTest, testresult^.TestResultSoftware)letrowCount=countRows--count the tests that passedpassed=count ( case_ [ when_ ( testresult^.TestResultPass==.valTrue) then_ (val$JustTrue)] (else_$valNothing))return$passed/.val1.0*.rowCountgetSoftwareOSScores::MonadIOm=>...
COUNT(*) FROM users auto usersCount = storage.count<User>(); cout << "users count = " << usersCount << endl; // users count = 8 // SELECT COUNT(id) FROM users auto countId = storage.count(&User::id); cout << "countId = " << countId << endl; // countId = 8 // ...
alter table vacancyadd column salary_net integer as (case when salary_gross = true thenround(salary_from/1.04)elsesalary_fromend 生成列可以像其他普通字段一样查询: selectsubstr(name, 1, 40) as name,salary_netfrom vacancywheresalary_currency = 'JPY'and salary_net is not nulllimit 10; ...
select max(continuousdays)from (select count(*) continuousdaysfrom (select sum(risingflag) over (order by day) norisingdaysfrom (select day, case when price>lag(price) over (order by day) then 0 else 1 end risingflag from tbl)) group by norisingdays) ...