果然,用了SUM函数之后,SQL语句变简单了,效率也大大提高了! SELECTdate,SUM(caseresultwhen'win'then1else0end)ASwin,SUM(caseresultwhen'lose'then1else0end)ASloseFROMinfoGROUPBYdateORDERBYdate; 测试完了,删除测试表: DROPTABLEinfo; 参考资料: http://www.yiibai.com/mysql/case-function.html http://www...
You could use the CASE function in a SQL statement where theexpressionis included. SELECT supplier_id, CASE quantity WHEN > 10 THEN 'The quantity is greater than 10' WHEN = 10 THEN 'The quantity is 10' ELSE 'The quantity is something else' END FROM suppliers; ...
MySQLCASEFunction ❮Previous❮ MySQL FunctionsNext❯ ExampleGet your own SQL Server Go through conditions and return a value when the first condition is met: SELECTOrderID, Quantity, CASE WHENQuantity >30THEN"The quantity is greater than 30" ...
SQL USEAdventureWorks2022; GOCREATEFUNCTIONdbo.GetContactInformation (@BusinessEntityIDINT)RETURNS@retContactInformationTABLE( BusinessEntityIDINTNOTNULL, FirstNameNVARCHAR(50)NULL, LastNameNVARCHAR(50)NULL, ContactTypeNVARCHAR(50)NULL, PRIMARYKEYCLUSTERED (BusinessEntityIDASC) )AS-- Returns the first name...
PostgreSQL是一种开源的关系型数据库管理系统(RDBMS),它支持广泛的标准SQL语言,并提供了丰富的功能和扩展性。在PostgreSQL中,CASE/WHEN是一种条件表达式,用于根据给定的条件返回不同的结果。 当在使用CASE/WHEN表达式时,如果出现错误,可能是由于以下几个原因: ...
SQL Lower The opposite of the upper function is lower function. This function takes a string and returns all the alphabetic characters in lowercase. Example: SELECT LOWER('LINUXHINT'); This should return the previous string in lowercase.
or a customer. The function returns the first and last name of a givenBusinessEntityIDand the contact type for that person. TheCASEexpression in the SET statement determines the value to display for the columnContactTypebased on the existence of theBusinessEntityIDcolumn in theEmployee,Vendor, ...
SQL USEAdventureWorks2022; GOCREATEFUNCTIONdbo.GetContactInformation (@BusinessEntityIDINT)RETURNS@retContactInformationTABLE( BusinessEntityIDINTNOTNULL, FirstNameNVARCHAR(50)NULL, LastNameNVARCHAR(50)NULL, ContactTypeNVARCHAR(50)NULL, PRIMARYKEYCLUSTERED (BusinessEntityIDASC) )AS-- Returns the first name...
表语句： DROP TABLE IF EXISTS `yj_item_plan`; CREATE TABLE `yj_item_plan` ( `id` big...
执行此T-Sql,报错:Error converting data type nvarchar to float. 3.我们使用同样的Table,只是稍微改动Value,结果如下: TestTable 执行此T-Sql,我们会得到同样的错误。 针对上面这个问题,我们最终找到的问题是: 使用Case语句时,前后的数据类型不匹配造成的,不管你实际的结果是不是完全满足最终你想要的格式,在Case...