fix(presto): fix parsing and generating hash functions presto/trino

[viplazylmht]

Fixes #3458

Affected functions:

• MD5_DIGEST
• MD5
• SHA
• SHA2

[tobymao]

this seems repeated from clickhouse, can we add this into dialects and make it so clickhouse and presto both use these implementations

in dialects, you can create a dict

{ "MD5": ..., } and then import that dict here and clickhouse and put it in both places

[viplazylmht]

I don't think that is a good idea.

Do you mean I can implement like this? This way just fit for Parser, but the Generator are vary and depends on dialects (e.g. when generating exp.MD5)

diff --git a/sqlglot/dialects/dialect.py b/sqlglot/dialects/dialect.py
index cc1d6208..c42fadbb 100644
--- a/sqlglot/dialects/dialect.py
+++ b/sqlglot/dialects/dialect.py
@@ -19,6 +19,11 @@ DATE_ADD_OR_DIFF = t.Union[exp.DateAdd, exp.TsOrDsAdd, exp.DateDiff, exp.TsOrDsD
 DATE_ADD_OR_SUB = t.Union[exp.DateAdd, exp.TsOrDsAdd, exp.DateSub]
 JSON_EXTRACT_TYPE = t.Union[exp.JSONExtract, exp.JSONExtractScalar]
 
+HASH_FUNCTION_PARSER: t.Dict[str, t.Callable[[t.List], exp.Func]] = {
+    "MD5": exp.MD5Digest.from_arg_list,
+    "SHA256": lambda args: exp.SHA2(this=seq_get(args, 0), length=exp.Literal.number(256)),
+    "SHA512": lambda args: exp.SHA2(this=seq_get(args, 0), length=exp.Literal.number(512)),
+}
 
 if t.TYPE_CHECKING:
     from sqlglot._typing import B, E, F
diff --git a/sqlglot/dialects/bigquery.py b/sqlglot/dialects/bigquery.py
index 0d2cfc1a..54c8a2ed 100644
--- a/sqlglot/dialects/bigquery.py
+++ b/sqlglot/dialects/bigquery.py
@@ -25,6 +25,7 @@ from sqlglot.dialects.dialect import (
     timestrtotime_sql,
     ts_or_ds_add_cast,
     unit_to_var,
+    HASH_FUNCTION_PARSER,
 )
 from sqlglot.helper import seq_get, split_num_words
 from sqlglot.tokens import TokenType
@@ -313,6 +314,7 @@ class BigQuery(Dialect):
 
         FUNCTIONS = {
             **parser.Parser.FUNCTIONS,
+            **HASH_FUNCTION_PARSER,
             "DATE": _build_date,
             "DATE_ADD": build_date_delta_with_interval(exp.DateAdd),
             "DATE_SUB": build_date_delta_with_interval(exp.DateSub),
@@ -330,7 +332,6 @@ class BigQuery(Dialect):
             "JSON_EXTRACT_SCALAR": lambda args: exp.JSONExtractScalar(
                 this=seq_get(args, 0), expression=seq_get(args, 1) or exp.Literal.string("$")
             ),
-            "MD5": exp.MD5Digest.from_arg_list,
             "TO_HEX": _build_to_hex,
             "PARSE_DATE": lambda args: build_formatted_time(exp.StrToDate, "bigquery")(
                 [seq_get(args, 1), seq_get(args, 0)]
@@ -344,8 +345,6 @@ class BigQuery(Dialect):
                 occurrence=seq_get(args, 3),
                 group=exp.Literal.number(1) if re.compile(args[1].name).groups == 1 else None,
             ),
-            "SHA256": lambda args: exp.SHA2(this=seq_get(args, 0), length=exp.Literal.number(256)),
-            "SHA512": lambda args: exp.SHA2(this=seq_get(args, 0), length=exp.Literal.number(512)),
             "SPLIT": lambda args: exp.Split(
                 # https://cloud.google.com/bigquery/docs/reference/standard-sql/string_functions#split
                 this=seq_get(args, 0),
diff --git a/sqlglot/dialects/clickhouse.py b/sqlglot/dialects/clickhouse.py
index 362ccde3..f4393ece 100644
--- a/sqlglot/dialects/clickhouse.py
+++ b/sqlglot/dialects/clickhouse.py
@@ -15,6 +15,7 @@ from sqlglot.dialects.dialect import (
     build_json_extract_path,
     rename_func,
     var_map_sql,
+    HASH_FUNCTION_PARSER,
 )
 from sqlglot.helper import is_int, seq_get
 from sqlglot.tokens import Token, TokenType
@@ -120,6 +121,7 @@ class ClickHouse(Dialect):
 
         FUNCTIONS = {
             **parser.Parser.FUNCTIONS,
+            **HASH_FUNCTION_PARSER,
             "ANY": exp.AnyValue.from_arg_list,
             "ARRAYSUM": exp.ArraySum.from_arg_list,
             "COUNTIF": _build_count_if,
@@ -146,9 +148,6 @@ class ClickHouse(Dialect):
             "TUPLE": exp.Struct.from_arg_list,
             "UNIQ": exp.ApproxDistinct.from_arg_list,
             "XOR": lambda args: exp.Xor(expressions=args),
-            "MD5": exp.MD5Digest.from_arg_list,
-            "SHA256": lambda args: exp.SHA2(this=seq_get(args, 0), length=exp.Literal.number(256)),
-            "SHA512": lambda args: exp.SHA2(this=seq_get(args, 0), length=exp.Literal.number(512)),
         }
 
         AGG_FUNCTIONS = {
diff --git a/sqlglot/dialects/presto.py b/sqlglot/dialects/presto.py
index b6e44cb9..f151dff5 100644
--- a/sqlglot/dialects/presto.py
+++ b/sqlglot/dialects/presto.py
@@ -27,6 +27,7 @@ from sqlglot.dialects.dialect import (
     timestrtotime_sql,
     ts_or_ds_add_cast,
     unit_to_str,
+    HASH_FUNCTION_PARSER,
 )
 from sqlglot.dialects.hive import Hive
 from sqlglot.dialects.mysql import MySQL
@@ -233,6 +234,7 @@ class Presto(Dialect):
 
         FUNCTIONS = {
             **parser.Parser.FUNCTIONS,
+            **HASH_FUNCTION_PARSER,
             "ARBITRARY": exp.AnyValue.from_arg_list,
             "APPROX_DISTINCT": exp.ApproxDistinct.from_arg_list,
             "APPROX_PERCENTILE": _build_approx_percentile,
@@ -281,9 +283,6 @@ class Presto(Dialect):
             "TO_UTF8": lambda args: exp.Encode(
                 this=seq_get(args, 0), charset=exp.Literal.string("utf-8")
             ),
-            "MD5": exp.MD5Digest.from_arg_list,
-            "SHA256": lambda args: exp.SHA2(this=seq_get(args, 0), length=exp.Literal.number(256)),
-            "SHA512": lambda args: exp.SHA2(this=seq_get(args, 0), length=exp.Literal.number(512)),
         }
 
         FUNCTION_PARSERS = parser.Parser.FUNCTION_PARSERS.copy()

[georgesittas]

LGTM, I'd personally look into refactoring if we get ≥3 dialects repeating the same logic, but don't feel strongly about it.