Question

我试图将表的某些字段导出到csv文件中... 我正在使用的查询是

SELECT "field1", "field1", "field3"
UNION ALL
SELECT *
FROM mytable
INTO OUTFILE "/Users/davide/Documents/file.csv"
FIELDS TERMINATED BY ','
LINES TERMINATED BY '\n'

但mysql返回

ERROR 1222 (21000): The used SELECT statements have a different number of columns

桌上有2个字段，但我不知道＆＃39;认为这是问题。

由于

Answer 1

请勿使用SELECT *，列出要放入CSV的特定列。 SELECT *表示返回表格中的所有列。

SELECT "field1", "field1", "field3"
UNION ALL
SELECT field1, field2, field3
FROM mytable
INTO OUTFILE "/Users/davide/Documents/file.csv"
FIELDS TERMINATED BY ','
LINES TERMINATED BY '\n'

Answer 2

问题在于，当您使用UNION语句时，必须确保SELECT个语句具有相同的列数

如果您需要填写“空”空格，可以使用NULL，例如

SELECT "field1", "field1", "field3", NULL, NULL
UNION ALL
SELECT *
FROM mytable
INTO OUTFILE "/Users/davide/Documents/file.csv"
FIELDS TERMINATED BY ','
LINES TERMINATED BY '\n'

将MYSQL表导出为CSV。查询无效

2 个答案: