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我正在写一个SQL查询,这是我迄今为止。但是,尽管它们存在于数据库中,但不会显示结果。我已经看过,我只是没有看到它可能是错的。偶然的情况下,有人看到这里可能会出现什么错误吗?SQL查询不显示结果
SELECT customer_Name AS "Customer Name",
customer_Telephone AS "Customer Tel.",
rent_date AS "Date Out",
date_due AS "Date Due",
(bike_Number +' ' + bike_Model) AS "Bike No. and Model"
FROM rental_record
JOIN Customer using (customer_ID)
JOIN bike_Record using (bike_Number)
WHERE sysdate > date_Due
AND time_Actual = NULL
ORDER BY date_due DESC;
可以使用'='在SQL比不上'NULL'。您需要'time_actual IS NULL'来代替。 '+'不用于连接SQL中的字符串,您需要使用'||'作为它。你正在使用哪个DBMS? –
看起来像Oracle –
@AdrianLynch:then'bike_number +'''会引发错误。 –