Hi, All,
I tried the suggested approach and it works, but it requires to 'run' the
SQL statement first.
I just want to parse the SQL statement without running it, so I can do
this in my laptop without connecting to our production environment.
I tried to write a tool which uses the SqlBase.g4 bundled with SPARK SQL
to extract names of the input tables and it works as expected.
But I have a question:
The parser generated by SqlBase.g4 only accepts 'select' statement with
all keywords such as 'SELECT', 'FROM' and table names capitalized
e.g. it accepts 'SELECT * FROM FOO', but it doesn't accept 'select * from
foo'.
But I can run the spark.sql("select * from foo") in the spark2-shell
without any problem.
Is there another 'layer' in the SPARK SQL to capitalize those 'tokens'
before invoking the parser?
If so, why not just modify the SqlBase.g4 to accept lower cases keywords?
Thanks
Boying
发件人:
"Shahab Yunus" <shahab.yu...@gmail.com>
收件人:
"Ramandeep Singh Nanda" <ramannan...@gmail.com>
抄送:
"Tomas Bartalos" <tomas.barta...@gmail.com>, l...@china-inv.cn, "user
@spark/'user @spark'/spark users/user@spark" <user@spark.apache.org>
日期:
2019/01/24 06:45
主题:
Re: How to get all input tables of a SPARK SQL 'select' statement
Could be a tangential idea but might help: Why not use queryExecution and
logicalPlan objects that are available when you execute a query using
SparkSession and get a DataFrame back? The Json representation contains
almost all the info that you need and you don't need to go to Hive to get
this info.
Some details here:
https://jaceklaskowski.gitbooks.io/mastering-spark-sql/spark-sql-Dataset.html#queryExecution
On Wed, Jan 23, 2019 at 5:35 PM Ramandeep Singh Nanda <
ramannan...@gmail.com> wrote:
Explain extended or explain would list the plan along with the tables. Not
aware of any statements that explicitly list dependencies or tables
directly.
Regards,
Ramandeep Singh
On Wed, Jan 23, 2019, 11:05 Tomas Bartalos <tomas.barta...@gmail.com
wrote:
This might help:
show tables;
st 23. 1. 2019 o 10:43 <l...@china-inv.cn> napísal(a):
Hi, All,
We need to get all input tables of several SPARK SQL 'select' statements.
We can get those information of Hive SQL statements by using 'explain
dependency select....'.
But I can't find the equivalent command for SPARK SQL.
Does anyone know how to get this information of a SPARK SQL 'select'
statement?
Thanks
Boying
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