chore: Migrate GeoStDistanceOp operator to SQLGlot

bigframes/core/compile/sqlglot/expressions/geo_ops.py

@@ -116,6 +116,11 @@ def _(expr: TypedExpr) -> sge.Expression:
     return sge.func("SAFE.ST_Y", expr.expr)
 
 
+@register_binary_op(ops.GeoStDistanceOp, pass_op=True)
+def _(left: TypedExpr, right: TypedExpr, op: ops.GeoStDistanceOp) -> sge.Expression:
+    return sge.func("ST_DISTANCE", left.expr, right.expr, sge.convert(op.use_spheroid))
+
+
 @register_binary_op(ops.geo_st_difference_op)
 def _(left: TypedExpr, right: TypedExpr) -> sge.Expression:
     return sge.func("ST_DIFFERENCE", left.expr, right.expr)

tests/unit/core/compile/sqlglot/expressions/snapshots/test_geo_ops/test_geo_st_distance/out.sql

@@ -0,0 +1,15 @@
+WITH `bfcte_0` AS (
+  SELECT
+    `geography_col`
+  FROM `bigframes-dev`.`sqlglot_test`.`scalar_types`
+), `bfcte_1` AS (
+  SELECT
+    *,
+    ST_DISTANCE(`geography_col`, `geography_col`, TRUE) AS `bfcol_1`,
+    ST_DISTANCE(`geography_col`, `geography_col`, FALSE) AS `bfcol_2`
+  FROM `bfcte_0`
+)
+SELECT
+  `bfcol_1` AS `spheroid`,
+  `bfcol_2` AS `no_spheroid`
+FROM `bfcte_1`

tests/unit/core/compile/sqlglot/expressions/test_geo_ops.py

@@ -81,6 +81,21 @@ def test_geo_st_convexhull(scalar_types_df: bpd.DataFrame, snapshot):
     snapshot.assert_match(sql, "out.sql")
 
 
+def test_geo_st_distance(scalar_types_df: bpd.DataFrame, snapshot):
+    col_name = "geography_col"
+    bf_df = scalar_types_df[[col_name]]
+
+    sql = utils._apply_ops_to_sql(
+        bf_df,
+        [
+            ops.GeoStDistanceOp(use_spheroid=True).as_expr(col_name, col_name),
+            ops.GeoStDistanceOp(use_spheroid=False).as_expr(col_name, col_name),
+        ],
+        ["spheroid", "no_spheroid"],
+    )
+    snapshot.assert_match(sql, "out.sql")
+
+
 def test_geo_st_difference(scalar_types_df: bpd.DataFrame, snapshot):
     col_name = "geography_col"
     bf_df = scalar_types_df[[col_name]]