SQL>show userUSER为"HR"SQL>SELECTfirst_name,last_name,department_id,2CASEdepartment_id3WHEN10THEN'Accounting'4WHEN20THEN'Sales'5WHEN30THEN'Finance'6ELSE'Other'7ENDdepartment_name8FROMemployees where rownum<2;FIRST_NAMELAST_NAMEDEPARTMENT_IDDEPARTMENT_NAME---Steven King90OtherSQL> ※测试使用的Orac...
group_id 不接受任何参数,如果某个特定的分组出现n次,那么grouo_id返回从0到n-1之间的整数。 如改写以上SQL为: select e.department_id , e.job_id, group_id(), avg(e.salary) from hr.employees e where e.department_id is not null and e.job_id is not null group by e.department_id, roll...
CASE表达式可以再SQL中实现if-then-else型的逻辑,9i及以上版本支持CASE表达式。 1. 使用简单CASE表达式 语法如下: CASE search_expression WHENexpression1 THEN result1 … ELSEdefault_result END store@PDB1> select product_id,product_type_id,caseproduct_type_id when 1 then'book' when 2 then'video' whe...
Oracle Database/ Release 21 SQL Language Reference CASEexpressions let you useIF...THEN...ELSElogic in SQL statements without having to invoke procedures. The syntax is: Description of the illustration case_expression.eps simple_case_expression::= ...
Oracle Function: Case and Decode CASE expression perform if-then-else logic in SQL without having to use PL/SQL. CASE works in a similar manner to DECODE(). CASE is ANSI-compliant. There are two types of CASE expressions: Simple case expressions use expressions to determine the returned ...
If you need to use this logic in many tables you could place it in a PL/SQL function. Then call this function in your SQL: FromOracle Database 23ai, theautomatic SQL transpilercan extract SQL expressions in PL/SQL. These are then part of the SQL statement, so at runtime it's as-...
Oracle SQL中的Case语句是一种条件表达式,用于根据不同的条件执行不同的操作。它可以在SELECT、UPDATE和DELETE语句中使用。 Case语句有两种形式:简单Case表达式和搜索Case表达式。 简单Case表达式:简单Case表达式用于将一个表达式与一系列可能的值进行比较,并在匹配时执行相应的操作。它的语法如下: 代码语言:txt 复制 CA...
The answer is that it can not. Contradicting estimates like this often indicate problems with the statistics. In this particular case it is because the Oracle database does not update the table statistics when creating a new index (see also“Oracle Statistics for Function-Based Indexes”). ...
Oracle SQL Case带Null sql oracle where-clause 我有一个简单的查询,它从绑定变量中获取输入。 CREATE TABLE "FRUITS" ( "FRUIT_NAME" VARCHAR2(100), "COLOR" VARCHAR2(100) ) ; insert into fruits (fruit_name, color) values ('Banana', 'Yellow') insert into fruits (fruit_name, color) values...
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