[breaking change] fix 265, log should be log10, and add ln

[jimexist]

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Closes #265.

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[alamb]

I think this is a good fix personally.

I recommend we add some sort of end to end sql test that runs these functions and compares the results, but otherwise 👍 from me. Any thoughts @jorgecarleitao or @seddonm1 ?

[alamb]

perhaps we should keep a log entry / alias to log10 for postgres compatibility?

[jimexist]

i guess it's kept at the https://github.com/apache/arrow-datafusion/pull/271/files#diff-97178da6c90bfcb5e3dc80f06248ac1aebdec5a0e0e1d8ea235e2f571b5badf8R227 level, not here.

[jimexist]

here the macro defs shall not allow dups

[seddonm1]

Definitely in favour of Postgres behaviour. 👍

[jimexist]

see #275

[jorgecarleitao]

I agree, @alamb . Postgres spec ftw 👍

Thanks @jimexist for this!

[jimexist]

@alamb I've added a test suite to make it future proof: #275

[alamb]

I gave it a little spin and it looks good. Thank you @jimexist !

> CREATE EXTERNAL TABLE t(a double) STORED AS CSV LOCATION '/tmp/foo.csv';
0 rows in set. Query took 0 seconds.
> select * from t;
+---------+
| a       |
+---------+
| 1       |
| 2       |
| 3       |
| 3.14159 |
+---------+
4 row in set. Query took 0 seconds.
> select log(a), log10(a) from t;
+---------------------+---------------------+
| log(a)              | log10(a)            |
+---------------------+---------------------+
| 0                   | 0                   |
| 0.3010299956639812  | 0.3010299956639812  |
| 0.47712125471966244 | 0.47712125471966244 |
| 0.4971495058611233  | 0.4971495058611233  |
+---------------------+---------------------+