但是那样增加消耗(两个Select部分),而且SQL语句会比较长。下面是一个是用Case函数来完成这个功能的例子: 代码 这样我们使用Select,完成对二维表的输出形式,充分显示了Case函数的强大。
select *,sum(销售数量) from myOrders会报错 改为:select *,sum(销售数量) over from myOrders则不会报错,并且在最后一列显示求和结果 例:求每个销售员的销量:select *,sum(销售数量) over(partition by 销售员) from myOrders select 销售员, 销售总金额=SUM(销售数量*销售价格), 称号= ( case when SU...
1，int类型转换varchar类型，不需要强制转换，可隐式转换：SELECT CASE 1 WHEN '1' THEN '可以转换' ELSE '不可以转换' END 2，cast转换方式：SELECT CASE CAST(1 AS VARCHAR(10)) WHEN '1' THEN '用CAST转换成功' ELSE '用CAST转换失败' END 3，convert转换方式：SELECT CASE CONVERT(VARCHAR...
print_r($matches); 运行的结果为： Array ( [0] => colo
where 子句中对字段进行 null 值判断，否则将导致引擎放弃使用索引而进行全表扫描，如： select id ...
CASE可用于允许使用有效表达式的任意语句或子句。 例如,可以在 SELECT、UPDATE、DELETE 和 SET 等语句以及 <select_list>、IN、WHERE、ORDER BY 和 HAVING 等子句中使用CASE。 Transact-SQL 语法约定 语法 适用于 SQL Server、Azure SQL 数据库和 Azure Synapse Analytics 的语法。
Improved logging to the Output window. Errors and status notifications can be viewed in the SqlToolsService or MSSQL channels. For a full list see thechange log. Using First, installVisual Studio Codethen installmssqlextension by pressingF1orctrl+shift+pto open command palette, selectInstall Exten...
To specify a property, use the following form in the JDBC data source configuration: property=value Note: All connection string property names are case-insensitive. For example, Password is the same as password.Table 3-1 SQL Server Connection Properties Property Description AlwaysReportTrigger...
Open an existing file with a .sql file extension or open a new text file (ctrl+n) and change the language mode to SQL by pressingctrl+k,mand selectSQL.mssqlcommands and functionalities are enabled in the SQL language mode in Visual Studio Code editor. ...