Better parsing of SHOW PRIMARY KEYS in snowflake #1204
Description
Seems that support for SHOW commands is very basic - i.e. command is interpreted as text.
I need to support https://docs.snowflake.com/en/sql-reference/sql/show-primary-keys and to be more exact: to be able to exact Table Identifier from statements like this:
show primary keys /* ODBC:ForeignKeysMetadataSource */ in table "PROD"."SOMEAPP"."PRODUCTS"For now I'm using this ugly patch that I based on similar functionality of mysql dialect:
import sqlglot
from sqlglot import TokenType
from sqlglot.dialects import Snowflake
def _show_parser(*args, **kwargs):
def _parse(self):
return self._parse_show_snowflake(*args, **kwargs)
return _parse
class _SnowflakeDialect(Snowflake):
"""Snowflake dialect with basic support for `show primary keys in table ...` command."""
class Tokenizer(Snowflake.Tokenizer):
COMMANDS = Snowflake.Tokenizer.COMMANDS - {
TokenType.SHOW,
}
KEYWORDS = {
"PRIMARY KEYS": TokenType.PSEUDO_TYPE, # fact I needed to add this was the biggest challenge to implement this - otherwise somehow it identified PRIMARY KEYS string as PRIMARY_KEY token and `s` text token (?!)
**Snowflake.Tokenizer.KEYWORDS
}
class Parser(Snowflake.Parser):
STATEMENT_PARSERS = {
**Snowflake.Parser.STATEMENT_PARSERS, # type: ignore
TokenType.SHOW: lambda self: self._parse_show(),
}
SHOW_PARSERS = {
**Snowflake.Parser.SHOW_PARSERS, # type: ignore
"PRIMARY KEYS": _show_parser("PRIMARY KEYS", target="IN TABLE"),
}
def _parse_show_snowflake(self, this, target=False, full=None, global_=None):
if target:
if isinstance(target, str):
self._match_text_seq(*target.split(" "))
target_id = self._parse_table()
else:
target_id = None
return self.expression(
sqlglot.expressions.Show,
this=this,
target=target_id,
full=full,
log=log,
**{"global": global_},
)Of course this is a hack, and probably breaks parsing of other SHOW commands.
P.S. ❤️ this library, I would hate having writing parsing of SQL-like things on my own