Why is the CASE Statement Important? The CASE WHEN statement is a valuable tool in SQL queries, offering several key benefits: Data transformation: enables you to create new columns based on the values of existing columns. Conditional aggregation: allows you to create aggregated values (e.g., ...
We can add as manyWHEN ... THENconditions as required in theCASEstatement. For example, -- multiple CASE conditions in SQLSELECTcustomer_id, first_name,CASEWHENcountry ='USA'THEN'United States of America'WHENcountry ='UK'THEN'United Kingdom'ENDAScountry_nameFROMCustomers; Run Code Here, the...
1topics: #CASE的两种基本用法2CASE OPERATOR3CASE STATEMENT45MariaDB [mysql]> helpcasestatement; #case的第一种用法6Name: 'CASE STATEMENT'7Description:8Syntax:9CASE case_value10WHEN when_value THEN statement_list11[WHEN when_value THEN statement_list] ...12[ELSE statement_list]13END CASE1415Or...
是一种在数据库中进行数据查询和处理的技术。内连接是指通过共享相同值的列将两个或多个表中的数据连接起来,以便获取相关的数据。 在使用CASE语句进行内连接时,可以根据特定的条件将两个或多个表中的数据进...
SQL CASE Syntax 1 2 3 4 5 CASEcase_value WHENwhen_valueTHENstatement_list [WHENwhen_valueTHENstatement_list] ... [ELSEstatement_list] ENDCASE CASE 搜索条件 1 2 3 4 5 6 7 SELECTOrderID, Quantity, CASE WHENQuantity > 30THEN"The quantity is greater than 30"...
在编程中,case表达式是一种条件语句,用于根据不同的条件执行不同的代码块。舍入是一种数学运算,用于将一个数值按照一定的规则进行近似取整。 在case表达式中的舍入,通常指的是在条件判断中对浮点数进...
SQL SELECTBusinessEntityID, LastName, TerritoryName, CountryRegionNameFROMSales.vSalesPersonWHERETerritoryNameISNOTNULLORDERBYCASECountryRegionNameWHEN'United States'THENTerritoryNameELSECountryRegionNameEND; GO D. Use CASE in an UPDATE statement
Adding aCASE STATEMENTpipeline step allows us to set the conditions for theWHENand theELSEjust like we did before, without having to type in the entire SQL syntax. Then after hiding the original ‘Provider’ column and using aREORDER COLUMNSstep and aPIVOT DATAstep we’ll get the same table...
CASE selector WHEN selector_value_1 THEN statements_1 WHEN selector_value_1 THEN statement_2 ... ELSE else_statements END CASE; Code language: PostgreSQL SQL dialect and PL/pgSQL (pgsql) Let’s examine the syntax of the simple CASE statement in detail: 1) selector The selector is an...
The CASE statement cannot have an ELSE NULL clause, and it is terminated with END CASE instead of END. For the first syntax, case_value is an expression. This value is compared to the when_value expression in each WHEN clause until one of them is equal. When an equal when_value is ...