SELECTcolumn1, column2, ...CASEWHENcondition1THENresult1WHENcondition2THENresult2-- Add more WHEN conditions and results as neededENDASalias_nameFROMtable_name; We can add as manyWHEN ... THENconditions as required in theCASEstatement. For example, -- multiple CASE conditions in SQLSELECTcusto...
case WHEN cast(`status` AS SIGNED) < 45 THEN '1' WHEN cast(`status` AS SIGNED) > 44 AND...
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 years'WHENDATEDIFF(YEAR,[...
SQL Joins on Multiple Conditions We can specify multiple conditions using the AND or OR operators in SQL. These operators allow us to define a set of Boolean expressions which are then evaluated and compared against the resulting set. We use the AND operator to ensure that all the specified c...
The output fromEXPLAINshowsALLin thetypecolumn when MySQL uses afull table scanto resolve a query. 慢SQL 分析与优化 https://mp.weixin.qq.com/s/CaSVhAJgycjjbCxAkII2ZA 从系统设计角度看,一个系统从设计搭建到数据逐步增长,SQL 执行效率可能会出现劣化,为继续支撑业务发展,我们需要对慢 SQL 进行分析和...
Interfaces are similar to classes; however, interfaces define method signatures, not implementations. The methods are implemented in classes declared to implement an interface. Multiple inheritance occurs when a single class simultaneously supports many interfaces....
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...
在case表达式sql中检查多个条件你可以使用string_split为了达到这个目的。
multiple conditional expressions in a single CASE expression. When you have multiple conditional expressions in your CASE clause, the first expression that evaluates to TRUE will be the code block that is evaluated by your TSQL statement. To better understand how the CASE expression works I will ...
They are not very dependable as compared to NATURAL JOINS when joining multiple tables The JOIN..ON clause is similar to the WHERE clause which limits rows with conditions An additional WHERE clause is mandatory when the JOIN..ON clause is used None of the above...