[SPARK-3371][SQL] Renaming a function expression with group by gives error

[ravipesala]

The following code gives error.

sqlContext.registerFunction("len", (s: String) => s.length)
sqlContext.sql("select len(foo) as a, count(1) from t1 group by len(foo)").collect() 

Because SQl parser creates the aliases to the functions in grouping expressions with generated alias names. So if user gives the alias names to the functions inside projection then it does not match the generated alias name of grouping expression.
This kind of queries are working in Hive.
So the fix I have given that if user provides alias to the function in projection then don't generate alias in grouping expression,use the same alias.

[SparkQA]

Can one of the admins verify this patch?

[marmbrus]

ok to test

[SparkQA]

QA tests have started for PR 2511 at commit f8ace79.

• This patch merges cleanly.

[SparkQA]

QA tests have finished for PR 2511 at commit f8ace79.

• This patch passes unit tests.
• This patch merges cleanly.
• This patch adds no public classes.

[AmplabJenkins]

Test PASSed.
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[marmbrus]

A simpler solution is to just not assignAliases to the grouping expressions (I'm not sure why we are. That is probably my mistake). That change also seems to also make your test case pass.

[ravipesala]

Yes @marmbrus , better we remove assignAliases to grouping expressions.Updated code as per that. Please review.

[SparkQA]

QA tests have started for PR 2511 at commit 9fb973f.

• This patch merges cleanly.

[SparkQA]

QA tests have finished for PR 2511 at commit 9fb973f.

• This patch passes unit tests.
• This patch merges cleanly.
• This patch adds no public classes.

[AmplabJenkins]

Test PASSed.
Refer to this link for build results (access rights to CI server needed):
https://amplab.cs.berkeley.edu/jenkins//job/SparkPullRequestBuilder/21173/

[marmbrus]

Thanks! Merged to master.