在 Apache Spark 2.0.0 中，是否可以从外部数据库获取查询(而不是获取整个表)?

使用pyspark:

from pyspark.sql import SparkSession火花 = SparkSession\.builder\.appName("spark play")\.getOrCreate()df = spark.read\.format("jdbc")\.option("url", "jdbc:mysql://localhost:port")\.option("dbtable", "schema.tablename")\.option("用户", "用户名")\.option("密码", "密码")\.加载()

我宁愿获取查询的结果集，而不是获取schema.tablename".

解决方案

同 1.x 可以传递有效的子查询作为 dbtable 参数例如:

<预><代码>....option("dbtable", "(SELECT foo, bar FROM schema.tablename) AS tmp")...

Using pyspark:

from pyspark.sql import SparkSession

spark = SparkSession\
    .builder\
    .appName("spark play")\
    .getOrCreate()    

df = spark.read\
    .format("jdbc")\
    .option("url", "jdbc:mysql://localhost:port")\
    .option("dbtable", "schema.tablename")\
    .option("user", "username")\
    .option("password", "password")\
    .load()

Rather than fetch "schema.tablename", I would prefer to grab the result set of a query.

解决方案

Same as in 1.x you can pass valid subquery as dbtable argument for example:

...
.option("dbtable", "(SELECT foo, bar FROM schema.tablename) AS tmp")
...