1 files changed, 109 insertions, 0 deletions
diff --git a/sqlglot/dialects/postgres.py b/sqlglot/dialects/postgres.py
new file mode 100644
index 0000000..61dff86
--- /dev/null
+++ b/sqlglot/dialects/postgres.py
@@ -0,0 +1,109 @@
+from sqlglot import exp
+from sqlglot.dialects.dialect import (
+    Dialect,
+    arrow_json_extract_scalar_sql,
+    arrow_json_extract_sql,
+    format_time_lambda,
+    no_paren_current_date_sql,
+    no_tablesample_sql,
+    no_trycast_sql,
+)
+from sqlglot.generator import Generator
+from sqlglot.parser import Parser
+from sqlglot.tokens import Tokenizer, TokenType
+
+
+def _date_add_sql(kind):
+    def func(self, expression):
+        from sqlglot.optimizer.simplify import simplify
+
+        this = self.sql(expression, "this")
+        unit = self.sql(expression, "unit")
+        expression = simplify(expression.args["expression"])
+
+        if not isinstance(expression, exp.Literal):
+            self.unsupported("Cannot add non literal")
+
+        expression = expression.copy()
+        expression.args["is_string"] = True
+        expression = self.sql(expression)
+        return f"{this} {kind} INTERVAL {expression} {unit}"
+
+    return func
+
+
+class Postgres(Dialect):
+    null_ordering = "nulls_are_large"
+    time_format = "'YYYY-MM-DD HH24:MI:SS'"
+    time_mapping = {
+        "AM": "%p",  # AM or PM
+        "D": "%w",  # 1-based day of week
+        "DD": "%d",  # day of month
+        "DDD": "%j",  # zero padded day of year
+        "FMDD": "%-d",  # - is no leading zero for Python; same for FM in postgres
+        "FMDDD": "%-j",  # day of year
+        "FMHH12": "%-I",  # 9
+        "FMHH24": "%-H",  # 9
+        "FMMI": "%-M",  # Minute
+        "FMMM": "%-m",  # 1
+        "FMSS": "%-S",  # Second
+        "HH12": "%I",  # 09
+        "HH24": "%H",  # 09
+        "MI": "%M",  # zero padded minute
+        "MM": "%m",  # 01
+        "OF": "%z",  # utc offset
+        "SS": "%S",  # zero padded second
+        "TMDay": "%A",  # TM is locale dependent
+        "TMDy": "%a",
+        "TMMon": "%b",  # Sep
+        "TMMonth": "%B",  # September
+        "TZ": "%Z",  # uppercase timezone name
+        "US": "%f",  # zero padded microsecond
+        "WW": "%U",  # 1-based week of year
+        "YY": "%y",  # 15
+        "YYYY": "%Y",  # 2015
+    }
+
+    class Tokenizer(Tokenizer):
+        KEYWORDS = {
+            **Tokenizer.KEYWORDS,
+            "SERIAL": TokenType.AUTO_INCREMENT,
+            "UUID": TokenType.UUID,
+        }
+
+    class Parser(Parser):
+        STRICT_CAST = False
+        FUNCTIONS = {
+            **Parser.FUNCTIONS,
+            "TO_TIMESTAMP": format_time_lambda(exp.StrToTime, "postgres"),
+            "TO_CHAR": format_time_lambda(exp.TimeToStr, "postgres"),
+        }
+
+    class Generator(Generator):
+        TYPE_MAPPING = {
+            **Generator.TYPE_MAPPING,
+            exp.DataType.Type.TINYINT: "SMALLINT",
+            exp.DataType.Type.FLOAT: "REAL",
+            exp.DataType.Type.DOUBLE: "DOUBLE PRECISION",
+            exp.DataType.Type.BINARY: "BYTEA",
+        }
+
+        TOKEN_MAPPING = {
+            TokenType.AUTO_INCREMENT: "SERIAL",
+        }
+
+        TRANSFORMS = {
+            **Generator.TRANSFORMS,
+            exp.JSONExtract: arrow_json_extract_sql,
+            exp.JSONExtractScalar: arrow_json_extract_scalar_sql,
+            exp.JSONBExtract: lambda self, e: f"{self.sql(e, 'this')}#>{self.sql(e, 'path')}",
+            exp.JSONBExtractScalar: lambda self, e: f"{self.sql(e, 'this')}#>>{self.sql(e, 'path')}",
+            exp.CurrentDate: no_paren_current_date_sql,
+            exp.CurrentTimestamp: lambda *_: "CURRENT_TIMESTAMP",
+            exp.DateAdd: _date_add_sql("+"),
+            exp.DateSub: _date_add_sql("-"),
+            exp.StrToTime: lambda self, e: f"TO_TIMESTAMP({self.sql(e, 'this')}, {self.format_time(e)})",
+            exp.TimeToStr: lambda self, e: f"TO_CHAR({self.sql(e, 'this')}, {self.format_time(e)})",
+            exp.TableSample: no_tablesample_sql,
+            exp.TryCast: no_trycast_sql,
+        }