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:
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")
...
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