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author | jyotiska <jyotiska123@gmail.com> | 2014-10-01 13:52:50 -0700 |
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committer | Michael Armbrust <michael@databricks.com> | 2014-10-01 13:52:50 -0700 |
commit | 17333c7a3c26ca6d28e8f3ca097da37d6b655217 (patch) | |
tree | 6b116dcf9b5e50f3c37bf3c1d12815d4f6e925e9 /examples | |
parent | b81ee0b46d63c2122b88941696654100fd736942 (diff) | |
download | spark-17333c7a3c26ca6d28e8f3ca097da37d6b655217.tar.gz spark-17333c7a3c26ca6d28e8f3ca097da37d6b655217.tar.bz2 spark-17333c7a3c26ca6d28e8f3ca097da37d6b655217.zip |
Python SQL Example Code
SQL example code for Python, as shown on [SQL Programming Guide](https://spark.apache.org/docs/1.0.2/sql-programming-guide.html)
Author: jyotiska <jyotiska123@gmail.com>
Closes #2521 from jyotiska/sql_example and squashes the following commits:
1471dcb [jyotiska] added imports for sql
b25e436 [jyotiska] pep 8 compliance
43fd10a [jyotiska] lines broken to maintain 80 char limit
b4fdf4e [jyotiska] removed blank lines
83d5ab7 [jyotiska] added inferschema and applyschema to the demo
306667e [jyotiska] replaced blank line with end line
c90502a [jyotiska] fixed new line
4939a70 [jyotiska] added new line at end for python style
0b46148 [jyotiska] fixed appname for python sql example
8f67b5b [jyotiska] added python sql example
Diffstat (limited to 'examples')
-rw-r--r-- | examples/src/main/python/sql.py | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/examples/src/main/python/sql.py b/examples/src/main/python/sql.py new file mode 100644 index 0000000000..eefa022f19 --- /dev/null +++ b/examples/src/main/python/sql.py @@ -0,0 +1,73 @@ +# +# Licensed to the Apache Software Foundation (ASF) under one or more +# contributor license agreements. See the NOTICE file distributed with +# this work for additional information regarding copyright ownership. +# The ASF licenses this file to You under the Apache License, Version 2.0 +# (the "License"); you may not use this file except in compliance with +# the License. You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. +# + +import os + +from pyspark import SparkContext +from pyspark.sql import SQLContext +from pyspark.sql import Row, StructField, StructType, StringType, IntegerType + + +if __name__ == "__main__": + sc = SparkContext(appName="PythonSQL") + sqlContext = SQLContext(sc) + + # RDD is created from a list of rows + some_rdd = sc.parallelize([Row(name="John", age=19), + Row(name="Smith", age=23), + Row(name="Sarah", age=18)]) + # Infer schema from the first row, create a SchemaRDD and print the schema + some_schemardd = sqlContext.inferSchema(some_rdd) + some_schemardd.printSchema() + + # Another RDD is created from a list of tuples + another_rdd = sc.parallelize([("John", 19), ("Smith", 23), ("Sarah", 18)]) + # Schema with two fields - person_name and person_age + schema = StructType([StructField("person_name", StringType(), False), + StructField("person_age", IntegerType(), False)]) + # Create a SchemaRDD by applying the schema to the RDD and print the schema + another_schemardd = sqlContext.applySchema(another_rdd, schema) + another_schemardd.printSchema() + # root + # |-- age: integer (nullable = true) + # |-- name: string (nullable = true) + + # A JSON dataset is pointed to by path. + # The path can be either a single text file or a directory storing text files. + path = os.environ['SPARK_HOME'] + "examples/src/main/resources/people.json" + # Create a SchemaRDD from the file(s) pointed to by path + people = sqlContext.jsonFile(path) + # root + # |-- person_name: string (nullable = false) + # |-- person_age: integer (nullable = false) + + # The inferred schema can be visualized using the printSchema() method. + people.printSchema() + # root + # |-- age: IntegerType + # |-- name: StringType + + # Register this SchemaRDD as a table. + people.registerAsTable("people") + + # SQL statements can be run by using the sql methods provided by sqlContext + teenagers = sqlContext.sql("SELECT name FROM people WHERE age >= 13 AND age <= 19") + + for each in teenagers.collect(): + print each[0] + + sc.stop() |