Question

现在当我将MYSQL表导出为CSV文件时，我得到\ N表示数据库中的NULL字段。如果有一种方法可以在将表导出到csv时将\ N输出更改为空字符串？

由于

SELECT 'CU_CustomerID','CU_UserName','CU_Password','CU_Email','CU_Company','CU_Comment','CU_LastBasket','CON_FirstName','CON_MiddleI','CON_LastName','CON_Address1','CON_Address2','CON_City','CON_State','CON_Province','CON_Country','CON_Zip','CON_Phone1','CON_Phone2'
UNION
SELECT T1.CU_CustomerID,T1.CU_UserName,T1.CU_Password,T1.CU_Email,T1.CU_Company,T1.CU_Comment,T1.CU_ShopperPoints,T2.CON_FirstName,T2.CON_MiddleI,T2.CON_LastName,T2.CON_Address1,T2.CON_Address2,T2.CON_City,T2.CON_State,T2.CON_Province,T2.CON_Country,T2.CON_Zip,T2.CON_Phone1,T2.CON_Phone2
FROM CUSTOMERS AS T1
INNER JOIN CONTACT AS T2 ON T1.CU_CustomerID = T2.CON_CustomerID
WHERE T1.CU_CustomerID BETWEEN 0 AND 1000
INTO OUTFILE  'customers.csv'
FIELDS TERMINATED BY  ','
ENCLOSED BY  '"'

Answer 1

来自MySQL documentation

如果FIELDS ESCAPED BY字符为空，则不会转义任何字符并且NULL输出为NULL，而不是\ N.指定一个空的转义字符可能不是一个好主意，特别是如果数据中的字段值包含刚刚给出的列表中的任何字符。

Answer 2

以防万一。为避免键入＆＃34; ifnull（var，＆＃39;＆＃39;）为var＆＃34;对于每个变量，可以使用它：

SELECT GROUP_CONCAT(CONCAT("IFNULL(",COLUMN_NAME,",'') AS ", COLUMN_NAME))
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = '<table name>'
AND TABLE_SCHEMA = '<schema name>'
ORDER BY ORDINAL_POSITION

Answer 3

硬道： -

SELECT 'CU_CustomerID','CU_UserName','CU_Password','CU_Email','CU_Company','CU_Comment','CU_LastBasket','CON_FirstName','CON_MiddleI','CON_LastName','CON_Address1','CON_Address2','CON_City','CON_State','CON_Province','CON_Country','CON_Zip','CON_Phone1','CON_Phone2'
UNION
SELECT COALESCE(T1.CU_CustomerID,''),COALESCE(T1.CU_UserName,''),COALESCE(T1.CU_Password,''),COALESCE(T1.CU_Email,''),COALESCE(T1.CU_Company,''),COALESCE(T1.CU_Comment,''),COALESCE(T1.CU_ShopperPoints,''),COALESCE(T2.CON_FirstName,''),COALESCE(T2.CON_MiddleI,''),COALESCE(T2.CON_LastName,''),COALESCE(T2.CON_Address1,''),COALESCE(T2.CON_Address2,''),COALESCE(T2.CON_City,''),COALESCE(T2.CON_State,''),COALESCE(T2.CON_Province,''),COALESCE(T2.CON_Country,''),COALESCE(T2.CON_Zip,''),COALESCE(T2.CON_Phone1,''),COALESCE(T2.CON_Phone2,'')
FROM CUSTOMERS AS T1
INNER JOIN CONTACT AS T2 ON T1.CU_CustomerID = T2.CON_CustomerID
WHERE T1.CU_CustomerID BETWEEN 0 AND 1000
INTO OUTFILE  'customers.csv'
FIELDS TERMINATED BY  ','
ENCLOSED BY  '"'

这会将所有值默认为空字符串而不是NULL（'\ N'）。

Answer 4

我也有这个问题，解决方法如下：

选择ifnull（addr。reference，“”）AS reference，来自...的data2

将MYSQL表导出为CSV时如何处理空字段

4 个答案: