Question

我尝试了以下sqoop命令。它适用于联接两个表，但不适用于多个表：

sqoop import 
--connect jdbc:mysql://<ip>:6306/siki_asmet?zeroDateTimeBehavior=convertToNull 
--username micronics -P 
--query "SELECT * from bu FULL JOIN bu_brbu USING(id_bu) FULL JOIN bu_jenis USING(id_jenis_bu) WHERE \$CONDITIONS" 
--split-by bu.id_bu 
--target-dir /user/hadoop/joinbu -m 1;

它说语法有误：

ERROR manager.SqlManager: Error executing statement: java.sql.SQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'FULL JOIN bu_jenis USING(id_jenis_bu) WHERE  (1 = 0)' at line 1
java.sql.SQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'FULL JOIN bu_jenis USING(id_jenis_bu) WHERE  (1 = 0)' at line 1
at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:120)

我不能使用JOIN ON，因为这样会给我错误，指出无法识别列。有帮助吗？

Answer 1

MySQL中没有FULL JOIN。

您可以使用左连接（或左和右）的并集来模拟它。您可以在下面根据表格查看示例：

Select * from bu left join bu_brbu on condition
union all
select * from bu right join bu_brbu on condition

使用MySQL数据库中的Sqoop联接多个表？

1 个答案: