Elliot Wilkinson

[Feature Request]: Add Missing PGSQL Functions

1

### Topic Support new SQL ### Description The [PostgreSqlLexer.g4](https://github.com/DTStack/dt-sql-parser/blob/main/src/grammar/postgresql/PostgreSqlLexer.g4) is missing support for common Postgres functions [TO_CHAR](https://www.postgresql.org/docs/17/functions-formatting.html) and [DATE_TRUNC](https://www.postgresql.org/docs/17/functions-datetime.html) Please can these be added. This is an issue since basic...