For instance, we have the columnsid,name, andis_activein theColumnstable. Theis_activecolumn indicates whether a course is currently being offered. We can use a simple CASE statement to transform theis_activevalues into more descriptive labels: SELECTid, name,CASEis_activeWHEN'Yes'THEN'Active'...
I vaguely remember using a case clause in a select statement in a former occupation, but now that I am using mysql (with php) I am encountering my first need for it and don't know if I can do what I want. I need to add a sequencing field to my query results based upon whether ...
TheCase Elseclause is used to indicate theelsestatementsto be executed if no match is found between thetestexpressionand anexpressionlistin any of the otherCaseselections. Although not required, it is a good idea to have aCase Elsestatement in yourSelect Caseblock to handle unforeseentestexpression...
if语句 在查询中使用if,语法如下: if('表达式','真值','假值'). 比如在数据中库存储的性别字段为1或者0,查询时想获取男,女...case语句 当两种选择是可以使用if,有多种选择的时候就需要case语句了...比如在上例子中,我们存储了一些不希望暴露性别的用户,存储的值为3.此时想要查询可以: select s.name ...
TheCase Elsestatement is used to introduce theelsestatementsto run if no match is found between thetestexpressionand anexpressionlistclause in any of the otherCasestatements. Although not required, it is a good idea to have aCase Elsestatement in yourSelect Caseconstruction to handle unforeseentest...
SELECT 语句中的子查询子查询(Sub Query)或者说内查询(Inner Query),也可以称作嵌套查询(Nested Query),是一种嵌套在其他 SQL 查询的 WHERE 子句中的查询...使用子查询必须遵循以下几个规则: 子查询必须括在圆括号中。 子查询的 SELECT 子句中只能有一个列,除.
In a <select-case-statement> the <select-expression> is immediately evaluated and then used in the evaluation of each subsequent <case-clause> and <case-else-clause> For each <case-clause>, each contained <range-clause> is evaluated in the order defined. If a <range-clause>matchesa <sele...
TheCase Elseclause is used to indicate theelsestatementsto be executed if no match is found between thetestexpressionand anexpressionlistin any of the otherCaseselections. Although not required, it is a good idea to have aCase Elsestatement in yourSelect Caseblock to handle unforeseentestexpression...
CASE statement to create or formulate a query/expression. It can be used with any statement or clause where an expression can be used, such as with a WHERE clause, with the SELECT statement, etc. This post has presented various examples to explain the usage of the case statement in ...
A Case Else statement introduces statements to be executed if no match is found for the initial Case. A Case statement has been found after a Case Else in the same Select block.Error ID: BC30321To correct this errorMove the Case Else to the appropriate location after the Case statement...