1. Case Expression 可以用在SQL和PL/SQL中,关于Case Expression最重要的一点就是,这个Case语句最后是返回一个值的,不管是在SQL语句的Select, Order By, Where 字句中,归根结底每个Case Expression都是要返回一个值。 而且,用法上面,Case Expression 的结束标志是END, 不是END CASE!这点很重要,经常搞混淆了! -...
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 this example, if the deptno column has a 10 in it, the SQL query will return the value accounting rather than the number 10. If the deptno is not 10, 20, 30, or 40, then the CASE statement will fall through to the ELSE clause, which will return unassigned. Note that with a s...
You can use aCASEexpression in any statement or clause that accepts a valid expression. For example, you can use theCASEexpression in statements such asSELECT,UPDATE, orDELETE, and in clauses likeSELECT,WHERE,HAVING, andORDDER BY. OracleCASEexpression has two formats: the simpleCASEexpression ...
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-if the function doesn't exist! To do this, ensure thesql_transpilerparameter ison(it'soffby default). When a function in thewh...
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 statement in detail: 1) selector The selector is an...
Oracle decode函数 decode函数在Oracle SQL查询语句中的使用非常广泛,也经常应用到PL/SQL语句块中。...可以作如下理解该表达式: 1,如果expr1 = expr2,decode函数返回expr3表达式的值; 2,如果expr1 !...= expr2,decode函数返回expr4表达式的值,如果expr4未指定,则返回null; 使用示例1: select decode(1,-1,...
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...
selector-expressionの値が最初のmatch-expressionに等しい場合、対応するTHEN句のステートメントが実行され、END CASEキーワードに続いて制御が続行されます。 一致が見つからない場合、ELSEに続くステートメントが実行される。 一致が見つからず、ELSE句が存在しない場合、例外がスローされます。
Oracle Spatial and Graph - Version 11.2.0.3 and later: ORA-06592: CASE Not Found While Executing CASE Statement When Running SEM_MATCH Query