The SQLCASEstatement evaluates a list of conditions and adds a column with values based on the condition. For example, -- add a new column 'order_volume' in the Orders table-- and flag any order greater than 10000 as 'Large Order'-- and smaller than 10000 as 'Small Order'SELECT*,CASE...
NOTE: SQL commands are not case sensitive. The above SELECT statement can also be written as"select first_name from students_details;" You can also retrieve data from more than one column. For example, to select first name and last name of all the students. ...
数据查询语言(DQL,Data Query Language):用于从表中获得数据,关键字是SELECT 实际应用中,我们通常是编写SQL语句,提交给数据库或大数据系统来执行,然后获取执行结果;有几个容易搞迷糊的概念如下: Statement:语句,通常指整个SQL文本 Clause:子句,通常指SQL文本中的一部分,如From子句、Where子句、Group By子句 Query:查询...
In the following query, the CASE statement is used to return the different designations of the CUSTOMERS based on their AGE. The WHERE clause is used to filter the rows based on the SALARY of the CUSTOMERS −Open Compiler SELECT NAME, ADDRESS, CASE WHEN AGE < 25 THEN 'Intern' WHEN ...
在SQL Server中,SELECT语句用于从数据库中检索数据。CASE语句是SELECT语句中的一种条件表达式,用于根据条件返回不同的结果。 CASE语句有两种形式:简单CASE表达式和搜索CASE表达式。 简单CASE表达式:简单CASE表达式基于一个表达式进行比较,并根据匹配的结果返回相应的值。语法如下: 简单CASE表达式:简单CASE表达式基于一个表达式...
LOCKED]|LOCKINSHARE MODE]]SELECTisusedtoretrieve rows selectedfromoneormore tables,andcan includeUNIONstatementsandsubqueries. See[HELP UNION],andhttp://dev.mysql.com/doc/refman/8.0/en/subqueries.html. ASELECTstatement can startwithaWITHclausetodefine commontableexpressions accessible within theSELECT....
SQL Server在select内嵌套Case 、 下面的案例当前是select查询的一部分。本质上说,如果FreeStockQuantity为0,则使用另一个字段中的值,除非该值为0或null。然后,它将结果返回为“Quantity” CASE WHEN FreeStockQuantity <= 0 AND (AnalysisCode19 > 0 OR AnalysisCode19 is NOTNULL) THEN AnalysisCode19END AS...
With a simple case you can check if an input equals any listed key. If it does you can return a corresponding value. This structure of this is: This Evaluates<selector>once Works down the list ofwhenclauses, stopping on the first key that equals the<selector>and returning the correspondi...
SELECT contact_id, CASE WHEN website_id = 1 THEN 'TechOnTheNet.com' WHEN website_id = 2 THEN 'CheckYourMath.com' END With the ELSE clause omitted, if no condition was found to be true, the CASE statement would return NULL.
'SELECT *FROMpayments WHERE user=:1AND order=:2' USING DESCRIPTOR in_desc, DESCRIPTOR out_desc; 批量操作优化 c // 分配批量描述符 EXEC SQL ALLOCATE DESCRIPTOR batch_desc WITH MAX1000; // 预绑定列信息 for(inti=0;i<columns;i++) { ...