1. 查询语句 语法:select casefieldnamewhenexp1thenresult1whenexp2thenresult2end fromtbname 示例: selectid,name,casewhensal>3500then'中等收入'whensal>2500andsal<=3500then'低等收入'whensal<2500then'低保户'else'高等收入'endsalfromt1 ; 2. 作为条件 语法: caseexpwhenexp1thenstatement1;whenexp2th...
oracle select case语句 oracle select case语句 Oracle数据库中的SELECT CASE语句是一种条件选择语句,根据一定的条件执行不同的操作。以下是十个使用Oracle SELECT CASE语句的示例:1. 根据员工的工资等级查询员工姓名:```sql SELECT employee_name,CASE WHEN salary > 5000 THEN '高级员工'WHEN salary > 3000 ...
问在Oracle的Select Satement中使用Case返回多列EN我有一个sceanrio,其中我需要根据主select语句中的条件...
SELECT CASE WHEN condition1 THEN column1 WHEN condition2 THEN column2 ELSE column3 END AS column_alias1, CASE WHEN condition1 THEN column4 WHEN condition2 THEN column5 ELSE column6 END AS column_alias2 FROM your_table; 在这个示例中,我们使用了两个CASE表达式,每个表达式都有三个条件。根...
1. CASE语句具有如下结构 CASE SELECTOR WHEN EXPRESSION 1 THEN STATEMENT 1; WHEN EXPRESSSION 2 THEN STATEMENT 2; ... WHEN EXPRESSION N THEN STATEMENT N; ELSE STATEMENT N+1; END CASE; 保留字CASE标识CASE语句的开始。选择器决定哪个WHEN子句应该被执行。每个WHEN子句都包含一个EXPRESSION以及与之关联的...
SELECT CASE WHEN nvl(t1.id,-1) = nvl(t2.reference, -1) THEN t2.reference ELSE 1 END AS number_col FROM trans t LEFT JOIN trans t2 ON (t.id = t2.parent_id); 也可以将其作为没有case语句的子查询来尝试 SELECT t.id, NVL ((SELECT t2.reference FROM trans t2 WHERE t.id = t...
SUM(CASEWHENsex ='1'THENpopulationELSE0END),--男性人口 SUM(CASEWHENsex ='2'THENpopulationELSE0END)--女性人口 FROMTable_AGROUPBYcountry; 这样我们使用Select,完成对二维表的输出形式,充分显示了Case函数的强大。 三,在Check中使用Case函数。 在Check中使用Case函数在很多情况下都是非常不错的解决方法。可能...
B) Using CASE expression in a HAVING clause# Consider the followingorder_itemsandproductstables: In the following query, we use theCASEexpression in aHAVINGclause to restrict rows returned by theSELECTstatement. SELECTproduct_name, category_id,COUNT(product_id)FROMorder_itemsINNERJOINproductsUSING(pr...
oracle菜鸟学习之 select case when的使用 格式语法 case when 条件1 then action1 when 条件2 then action2 when 条件3 then action3 when 条件N then actionN else action end 1. 2. 3. 4. 5. 6. 7. 例子 判断现在是几月 SQL> select case substr('20181118',5,2) ...
The simple CASE statement has the following structure: 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 ...