Modifying Dialects

[smeyn]

Hi, I work at Google Cloud, specialising in BigQuery. I thin this is very valuable, congratulations for your contribution.

I wondered how to add to the BigQuery Dialect.

Currently the following is not parsed:

EXTRACT(DATE FROM txnstarttimestamp) AS txnstartdate

the error message is: Expected FROM after EXTRACT

How would I go about adding the change to parsing the EXTRACT phrase?

[tobymao]

diff --git a/sqlglot/parser.py b/sqlglot/parser.py
index 036b5a1..8d629f5 100644
--- a/sqlglot/parser.py
+++ b/sqlglot/parser.py
@@ -1554,7 +1554,7 @@ class Parser:
         return self._parse_window(this)

     def _parse_extract(self):
-        this = self._parse_var()
+        this = self._parse_var() or self._parse_type()

[tobymao]

this has been added in 6455068

[smeyn]

Hi thanks for the prompt reply. Unfortunately it is not just DATE

See this documentation on the EXTRACT function for detail.

In addition to DATE you need DAYOFWEEK, DA, DAYOFYEAR, WEEK, WEEK(),
ISOWEEK, MONTH, QUARTER, YEAR and ISOYEAR

WEEKDAY is one of SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, and SATURDAY

Cheers

[tobymao]

those all work, try out master

[tobymao]

python -m sqlglot "extract(tuesday from y)" --parse
(EXTRACT this:
  (VAR this: tuesday), expression:
  (COLUMN this:
    (IDENTIFIER this: y, quoted: False)))