SQL中的CASE WHEN使用 Case具有两种格式。简单Case函数和Case搜索函数。...如果使用Case函数,SQL代码如下: SELECT SUM(population), CASE country WHEN ‘中国’ THEN ‘亚洲’ WHEN ‘印度’ THEN ‘...但是那样增加消耗(两个Select部分),而且SQL语句会比较长。...三,在
在sql语句中使用if或case和multiple请注意，sql通常不考虑排序，因此结果可以按任何顺序返回，甚至可以使用...
This allows for multiple conditions even without nesting—unlike the ?: operator in other programming languages. On the other hand, nesting provides an inherent precedence among the conditions. A flat case expression does not have such an inherent precedence. To close that gap, SQL uses the ...
Evaluates a list of conditions and returns one of multiple possible result expressions. TheCASEexpression has two formats: The simpleCASEexpression compares an expression to a set of simple expressions to determine the result. The searchedCASEexpression evaluates a set of Boolean expressions to determin...
Evaluates a list of conditions and returns one of multiple possible result expressions. TheCASEexpression has two formats: The simpleCASEexpression compares an expression to a set of simple expressions to determine the result. The searchedCASEexpression evaluates a set of Boolean expressions to determin...
Nesting CASE Expressions With the searched CASE expression, we can have multiple WHEN conditions: SELECT [BusinessEntityID],[JobTitle],[HireDate],Seniority=CASE WHENDATEDIFF(YEAR,[HireDate],GETDATE())>10 THEN'Longer than 10 years'WHENDATEDIFF(YEAR,[HireDate],GETDATE())=10 THEN'Exactly 10 ye...
This article explores the useful function SQL IF statement inSQL Server. 本文探讨了SQL Server中有用的函数SQL IF语句。 介绍(Introduction) In real life, we make decisions based on the conditions. For example, look at the following conditions. ...
CASE expression each WHEN clause will contain a “Boolean_expression”. This “Boolean_expression” can be a simple Boolean expression with a single operator, or a complex Boolean expression with many different conditions. In addition, the searched CASE expression can use the full set of Boolean ...
A function can be schema bound only if the following conditions are true: The function is a Transact-SQL function. The user-defined functions and views referenced by the function are also schema-bound. The objects referenced by the function are referenced using a two-part name. The function ...
Logical operator: the operator that you want to use to define logical relationships between query conditions. The following operators are supported: (), AND, OR, ANDNOT, and RANK. You must specify operators in uppercase letters. The priorities of these operators are in the following sequence: ...