Merge remote-tracking branch 'github/main' into fix_cf_reuse_configs

Author: TrevorBergeron

bigframes/bigquery/_operations/table.py

@@ -19,8 +19,8 @@
 import google.cloud.bigquery
 import pandas as pd
 
+import bigframes.core.compile.sqlglot.sql as sg_sql
 import bigframes.core.logging.log_adapter as log_adapter
-import bigframes.core.sql.table
 import bigframes.session
 
 
@@ -80,14 +80,16 @@ def create_external_table(
     """
     import bigframes.pandas as bpd
 
-    sql = bigframes.core.sql.table.create_external_table_ddl(
-        table_name=table_name,
-        replace=replace,
-        if_not_exists=if_not_exists,
-        columns=columns,
-        partition_columns=partition_columns,
-        connection_name=connection_name,
-        options=options,
+    sql = sg_sql.to_sql(
+        sg_sql.create_external_table(
+            table_name=table_name,
+            replace=replace,
+            if_not_exists=if_not_exists,
+            columns=columns,
+            partition_columns=partition_columns,
+            connection_name=connection_name,
+            options=options,
+        )
     )
 
     if session is None:

bigframes/core/blocks.py

@@ -1822,9 +1822,9 @@ def melt(
         Arguments correspond to pandas.melt arguments.
         """
         # TODO: Implement col_level and ignore_index
-        value_labels: pd.Index = pd.Index(
-            [self.col_id_to_label[col_id] for col_id in value_vars]
-        )
+        value_labels: pd.Index = self.column_labels[
+            [self.value_columns.index(col_id) for col_id in value_vars]
+        ]
         id_labels = [self.col_id_to_label[col_id] for col_id in id_vars]
 
         unpivot_expr, (var_col_ids, unpivot_out, passthrough_cols) = unpivot(
@@ -3417,6 +3417,7 @@ def unpivot(
         joined_array, (labels_mapping, column_mapping) = labels_array.relational_join(
             array_value, type="cross"
         )
+
     new_passthrough_cols = [column_mapping[col] for col in passthrough_columns]
     # Last column is offsets
     index_col_ids = [labels_mapping[col] for col in labels_array.column_ids[:-1]]
@@ -3426,20 +3427,24 @@ def unpivot(
     unpivot_exprs: List[ex.Expression] = []
     # Supports producing multiple stacked ouput columns for stacking only part of hierarchical index
     for input_ids in unpivot_columns:
-        # row explode offset used to choose the input column
-        # we use offset instead of label as labels are not necessarily unique
-        cases = itertools.chain(
-            *(
-                (
-                    ops.eq_op.as_expr(explode_offsets_id, ex.const(i)),
-                    ex.deref(column_mapping[id_or_null])
-                    if (id_or_null is not None)
-                    else ex.const(None),
+        col_expr: ex.Expression
+        if not input_ids:
+            col_expr = ex.const(None, dtype=bigframes.dtypes.INT_DTYPE)
+        else:
+            # row explode offset used to choose the input column
+            # we use offset instead of label as labels are not necessarily unique
+            cases = itertools.chain(
+                *(
+                    (
+                        ops.eq_op.as_expr(explode_offsets_id, ex.const(i)),
+                        ex.deref(column_mapping[id_or_null])
+                        if (id_or_null is not None)
+                        else ex.const(None),
+                    )
+                    for i, id_or_null in enumerate(input_ids)
                 )
-                for i, id_or_null in enumerate(input_ids)
             )
-        )
-        col_expr = ops.case_when_op.as_expr(*cases)
+            col_expr = ops.case_when_op.as_expr(*cases)
         unpivot_exprs.append(col_expr)
 
     joined_array, unpivot_col_ids = joined_array.compute_values(unpivot_exprs)
@@ -3457,19 +3462,43 @@ def _pd_index_to_array_value(
     Create an ArrayValue from a list of label tuples.
     The last column will be row offsets.
     """
+    id_gen = bigframes.core.identifiers.standard_id_strings()
+    col_ids = [next(id_gen) for _ in range(index.nlevels)]
+    offset_id = next(id_gen)
+
     rows = []
     labels_as_tuples = utils.index_as_tuples(index)
     for row_offset in range(len(index)):
-        id_gen = bigframes.core.identifiers.standard_id_strings()
         row_label = labels_as_tuples[row_offset]
         row_label = (row_label,) if not isinstance(row_label, tuple) else row_label
         row = {}
-        for label_part, id in zip(row_label, id_gen):
-            row[id] = label_part if pd.notnull(label_part) else None
-        row[next(id_gen)] = row_offset
+        for label_part, col_id in zip(row_label, col_ids):
+            row[col_id] = label_part if pd.notnull(label_part) else None
+        row[offset_id] = row_offset
         rows.append(row)
 
-    return core.ArrayValue.from_pyarrow(pa.Table.from_pylist(rows), session=session)
+    if not rows:
+        dtypes_list = getattr(index, "dtypes", None)
+        if dtypes_list is None:
+            dtypes_list = (
+                [index.dtype] if hasattr(index, "dtype") else [pd.Float64Dtype()]
+            )
+
+        fields = []
+        for col_id, dtype in zip(col_ids, dtypes_list):
+            try:
+                pa_type = bigframes.dtypes.bigframes_dtype_to_arrow_dtype(dtype)
+            except Exception:
+                pa_type = pa.string()
+            fields.append(pa.field(col_id, pa_type))
+        fields.append(pa.field(offset_id, pa.int64()))
+        schema = pa.schema(fields)
+        pt = pa.Table.from_pylist([], schema=schema)
+    else:
+        pt = pa.Table.from_pylist(rows)
+        pt = pt.rename_columns([*col_ids, offset_id])
+
+    return core.ArrayValue.from_pyarrow(pt, session=session)
 
 
 def _resolve_index_col(

bigframes/core/compile/sqlglot/sql/__init__.py

@@ -21,7 +21,7 @@
     table,
     to_sql,
 )
-from bigframes.core.compile.sqlglot.sql.ddl import load_data
+from bigframes.core.compile.sqlglot.sql.ddl import create_external_table, load_data
 from bigframes.core.compile.sqlglot.sql.dml import insert, replace
 
 __all__ = [
@@ -33,6 +33,7 @@
     "table",
     "to_sql",
     # From ddl.py
+    "create_external_table",
     "load_data",
     # From dml.py
     "insert",