COALESCE … statement to return 0 as the alternative value when bonus value is NULL: SELECT emp_no, salary, from_date, to_date, COALESCE(bonus, 0) FROM salaries; In MySQL you can also use IFNULL function to return 0 as the alternative for the NULL values: SELECT emp_no, salary, ...
DROPTABLEIF EXISTS t_student;CREATETABLEt_student(idINT(11)unsignedNOTNULLAUTO_INCREMENT COMMENT'自增主键',nameVARCHAR(50)NOTNULLCOMMENT'名称',ageINT(3)COMMENT'年龄',remarkVARCHAR(500)NOTNULLDEFAULT''COMMENT'备注',primary key(id))COMMENT'学生信息';INSERTINTOt_student(name,age)VALUE('zhangsan',2...
Parameters: columnLabelthe label for the column specified with the SQL AS clause. If the SQL AS clause was not specified, then the label is the name of the column Returns: the column value; if the value is SQLNULL, the value returned is0 Throws:...
代码语言:javascript 代码运行次数:0 运行 AI代码解释 WITHaAS(SELECTDISTINCTround(SUM(x)over(ORDERBYn))x,round(SUM(y)over(ORDERBYn))yFROM(SELECTn,cos(trunc(n/20)*(1-1/5)*3.1415926)*2x,sin(trunc(n/20)*(1-1/5)*3.1415926)yFROM(SELECTrownum-1nFROMall_objectsWHERErownum<=20*5)))SELECT...
orderbycasewhenageisnullthen1else0endasc,ageasc orderbyIF(ISNULL(age),1,0),age 7、null与聚合函数 count(*)时,输出的是所有记录行数,包括列全为null的行。countvalue具体某个字段时,如count(value)不会统计null。 sum(value)忽视null。avg视为sum(value)/count(value),忽略null ...
select name,if(age isnull(name),0,age) age from person where name 1. 2. 3. 和if联用的时候,类似于ifnull函数 2) is distinct from\ is not distinct from—判断两列值是否不同\相同 其中, is not distinct from,A和B的数据类型、值不完全相同返回 false A和B的数据类型、值完全相同返回 true,...
IS [NOT] NULL 之外，还有一些数据库扩展的运算符可以用于空值比较：-- MySQL WHERE manager_id <=> NULL;-- PostgreSQL WHERE manager_id IS NOT DISTINCT FROM NULL;MySQL 中的 <=> 可以用于等值比较，支持两个 NULL 值；PostgreSQL 中的 IS [NOT] DISTINCT FROM 可以用于等值比较，支持两个 NULL 值。以...
commit;但如果你想表达的是:在yangao表中插入一条数据,如果存在(select * from yangao where(AGE3=4)) 这样的数据就提交的话,那么应该这么写: insert into yangao values (4, NULL, 1); select count(*) into n_count from yangao where (AGE3 = 4); if n_count > 0 then commit; end if;。
excel.Add(cnHeader);//字段中文描述excel.Add(enHeader);//字段名if(isNullTemplate) { dt.Clear(); }varcolumnSettingMap = columnSettings?.ToDictionary(r => r.FieldName, r => r);//生成excel columnSettingMap == null ? null :excel.WriteExcel(dt, savePath, cellRenderFun: (sheet, row, ...
($_.CookedValue +$avg) /2)),5) } |Format-Table} }write-host"Final_Running_Average: $([Math]::Round($avg, 5)) sec/transfer`n"if($avg-gt0.01) {Write-Host"There ARE indications of slow I/O performance on your system"}else{Write-Host"There is NO indication of slow I/O ...