我试图添加一个条目,这取决于MySQL中另一个表中的现有条目:但“解决方案”(我从之前询问的另一个问题得到)不是我的数据正确地工作,我不知道为什么......根据MYSQL第二部分中另一个表中的现有条目添加一个条目
下面是我从解决问题:
Add an entry depending on existing entry in another table with MYSQL
这里是我的查询,我创建必要的表和导入数据:
CREATE TABLE `EMailImport` (user_id VARCHAR(20), `E-Mail` VARCHAR(150));
LOAD DATA LOCAL INFILE 'C:/Users/xyz/Desktop/X/export.csv'
INTO TABLE `EMailImport`
FIELDS TERMINATED BY ';'
LINES TERMINATED BY '\n';
DELETE FROM `EMailImport` LIMIT 1;
CREATE INDEX X ON `EMailImport` (`E-Mail`);
CREATE TABLE ABC AS SELECT customerID, ordernumber, `customersEmail`
FROM orders GROUP BY `customersEmail`;
CREATE INDEX Y ON ABC (`customersEmail`);
这里有2个查询我想(我曾经在溶液):两者都是工作
SELECT ABC.*, CASE WHEN `customersEmail` IN (SELECT `E-Mail` FROM EMailImport) THEN 'Yes' ELSE 'No' end AS `Did the customer ordered already?` FROM ABC;
SELECT ABC.*,CASE WHEN EXISTS (SELECT * FROM EMailImport WHERE EMailImport.`E-Mail` = ABC.`customersEmail`) then 'yes' else 'no' end as `Did the customer ordered already?` from ABC;
,但他们告诉我“没有”为每个条目(什么是不正确的):哪里是错误/问题?
Info
:表ABC中列的数据类型为:customerID = int(10); ordernumber = varchar(50),customersEmail = varchar(255);
ABC是否包含有效数据? –
是的,约300.00条目/行 – AbsoluteBeginner