From ea0826d829253f3aa23fb2aee52e3a2ea1193b7f Mon Sep 17 00:00:00 2001
From: Phillip Cloud <417981+cpcloud@users.noreply.github.com>
Date: Wed, 11 Oct 2023 05:59:30 -0400
Subject: [PATCH] refactor(clickhouse): use sqlglot for `create_table`
 implementation

---
 ibis/backends/clickhouse/__init__.py | 117 +++++++++++++++++----------
 1 file changed, 74 insertions(+), 43 deletions(-)

diff --git a/ibis/backends/clickhouse/__init__.py b/ibis/backends/clickhouse/__init__.py
index 6077f58e52c4..69a49b21ee30 100644
--- a/ibis/backends/clickhouse/__init__.py
+++ b/ibis/backends/clickhouse/__init__.py
@@ -486,21 +486,10 @@ def raw_sql(
         self._log(query)
         return self.con.query(query, external_data=external_data, **kwargs)
 
-    def fetch_from_cursor(self, cursor, schema):
-        import pandas as pd
-
-        from ibis.formats.pandas import PandasData
-
-        df = pd.DataFrame.from_records(iter(cursor), columns=schema.names)
-        return PandasData.convert_table(df, schema)
-
     def close(self) -> None:
         """Close ClickHouse connection."""
         self.con.close()
 
-    def _fully_qualified_name(self, name: str, database: str | None) -> str:
-        return sg.table(name, db=database).sql(dialect="clickhouse")
-
     def get_schema(self, table_name: str, database: str | None = None) -> sch.Schema:
         """Return a Schema object for the indicated table and database.
 
@@ -673,21 +662,13 @@ def create_table(
         Table
             The new table
         """
-        tmp = "TEMPORARY " * temp
-        replace = "OR REPLACE " * overwrite
-
         if temp and overwrite:
-            raise com.IbisInputError("Cannot specify both temp and overwrite")
-
-        if not temp:
-            table = self._fully_qualified_name(name, database)
-        else:
-            table = name
-            database = None
-        code = f"CREATE {replace}{tmp}TABLE {table}"
+            raise com.IbisInputError(
+                "Cannot specify both `temp=True` and `overwrite=True` for ClickHouse"
+            )
 
         if obj is None and schema is None:
-            raise com.IbisError("The schema or obj parameter is required")
+            raise com.IbisError("The `schema` or `obj` parameter is required")
 
         if obj is not None and not isinstance(obj, ir.Expr):
             obj = ibis.memtable(obj, schema=schema)
@@ -695,39 +676,89 @@ def create_table(
         if schema is None:
             schema = obj.schema()
 
-        serialized_schema = ", ".join(
-            f"`{name}` {ClickhouseType.to_string(typ)}" for name, typ in schema.items()
+        this = sg.exp.Schema(
+            this=sg.table(name, db=database),
+            expressions=[
+                sg.exp.ColumnDef(
+                    this=sg.to_identifier(name), kind=ClickhouseType.from_ibis(typ)
+                )
+                for name, typ in schema.items()
+            ],
         )
-
-        code += f" ({serialized_schema}) ENGINE = {engine}"
-
-        if order_by is not None:
-            code += f" ORDER BY {', '.join(util.promote_list(order_by))}"
-        elif engine == "MergeTree":
-            # empty tuple to indicate no specific order when engine is
-            # MergeTree
-            code += " ORDER BY tuple()"
+        properties = [
+            # the engine cannot be quoted, since clickhouse won't allow e.g.,
+            # "File(Native)"
+            sg.exp.EngineProperty(this=sg.to_identifier(engine, quoted=False))
+        ]
+
+        if temp:
+            properties.append(sg.exp.TemporaryProperty())
+
+        if order_by is not None or engine == "MergeTree":
+            # engine == "MergeTree" requires an order by clause, which is the
+            # empty tuple if order_by is False-y
+            properties.append(
+                sg.exp.Order(
+                    expressions=[
+                        sg.exp.Ordered(
+                            this=sg.exp.Tuple(
+                                expressions=list(map(sg.column, order_by or ()))
+                            )
+                        )
+                    ]
+                )
+            )
 
         if partition_by is not None:
-            code += f" PARTITION BY {', '.join(util.promote_list(partition_by))}"
+            properties.append(
+                sg.exp.PartitionedByProperty(
+                    this=sg.exp.Schema(
+                        expressions=list(map(sg.to_identifier, partition_by))
+                    )
+                )
+            )
 
         if sample_by is not None:
-            code += f" SAMPLE BY {sample_by}"
+            properties.append(
+                sg.exp.SampleProperty(
+                    this=sg.exp.Tuple(expressions=list(map(sg.column, sample_by)))
+                )
+            )
 
         if settings:
-            kvs = ", ".join(f"{name}={value!r}" for name, value in settings.items())
-            code += f" SETTINGS {kvs}"
+            properties.append(
+                sg.exp.SettingsProperty(
+                    expressions=[
+                        sg.exp.SetItem(
+                            this=sg.exp.EQ(
+                                this=sg.to_identifier(name), expression=lit(value)
+                            )
+                        )
+                        for name, value in settings.items()
+                    ]
+                )
+            )
+
+        external_tables = {}
+        expression = None
 
         if obj is not None:
-            code += f" AS {self.compile(obj)}"
-            external_tables = self._collect_in_memory_tables(obj)
-        else:
-            external_tables = {}
+            expression = self._to_sqlglot(obj)
+            external_tables.update(self._collect_in_memory_tables(obj))
+
+        code = sg.exp.Create(
+            this=this,
+            kind="TABLE",
+            replace=overwrite,
+            expression=expression,
+            properties=sg.exp.Properties(expressions=properties),
+        )
 
         external_data = self._normalize_external_tables(external_tables)
 
         # create the table
-        self.con.raw_query(code, external_data=external_data)
+        sql = code.sql(self.name, pretty=True)
+        self.con.raw_query(sql, external_data=external_data)
 
         return self.table(name, database=database)