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! -...
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...
With yourcaseexpression in hand, using it is a matter of pasting it in the appropriate place in your SQL. How to use CASE for IF-THEN logic in SQL SELECT If you want to see the grade for each exam, select thecaseexpression like a regular column: It’s a good idea to give the ...
可以确定我们的操作是没有问题的,我们搜索一下oracle的select语句用法oracle select statement Oracle select语句解释https://www.oracletutorial.com.../ 在 Oracle 中,SELECT语句必须有一个FROM子句。...SQL 注入备忘单来找到Oracle数据库查询数据库版本的语句 SELECT banner FROM v$version SELECT version FROM v$ins...
SELECT a.c_tenantid, a.c_tacode, c_tradeacco, CASE CONCAT(CONCAT(CONCAT('F6' ,a.c_agencyno),c_taflag),a.c_businflag) WHEN '66003153' THEN ' ' ELSE c_cityno END c_cityno, a.c_fundcode, a.d_requestdate, d_requesttime, a.c_businflag, ...
by & select子句和CASE运算符中同时使用子查询EN下面来总计下之前的随笔中所说过的所有的SELECT子句的...
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...
#Import librariesimport cx_Oracleimport mysql.connectorimport pandas as pdfrom sqlalchemy import create_engine#Set Oralce Connectionconn = cx_Oracle.connect('test/test@192.168.19.111/orcl')#Open cursorcursor = conn.cursor()#buidling sql statement to select records from Oraclesql = "SELECT * ...
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...
l 触发频率:说明触发器内定义的动作被执行的次数。即语句级(STATEMENT)触发器和行级(ROW)触发器。 语句级(STATEMENT)触发器:是指当某触发事件发生时,该触发器只执行一次; 行级(ROW)触发器:是指当某触发事件发生时,对受到该操作影响的每一行数据,触发器都单独执行一次。