feat(exasol): implement median and approx_median

Author: jcrist

ibis/backends/sql/compilers/exasol.py

@@ -32,7 +32,6 @@ class ExasolCompiler(SQLGlotCompiler):
 
     UNSUPPORTED_OPS = (
         ops.AnalyticVectorizedUDF,
-        ops.ApproxMedian,
         ops.ArgMax,
         ops.ArgMin,
         ops.ArrayDistinct,
@@ -56,7 +55,6 @@ class ExasolCompiler(SQLGlotCompiler):
         ops.IsInf,
         ops.IsNan,
         ops.Levenshtein,
-        ops.Median,
         ops.MultiQuantile,
         ops.RandomUUID,
         ops.ReductionVectorizedUDF,
@@ -187,6 +185,11 @@ def visit_CountDistinctStar(self, op, *, arg, where):
             "COUNT(DISTINCT *) is not supported in Exasol"
         )
 
+    def visit_Median(self, op, *, arg, where):
+        return self.visit_Quantile(op, arg=arg, quantile=sge.convert(0.5), where=where)
+
+    visit_ApproxMedian = visit_Median
+
     def visit_Quantile(self, op, *, arg, quantile, where):
         suffix = "cont" if op.arg.dtype.is_numeric() else "disc"
         funcname = f"percentile_{suffix}"

ibis/backends/tests/test_aggregation.py

@@ -1175,7 +1175,7 @@ def test_corr_cov(
 
 
 @pytest.mark.notimpl(
-    ["mysql", "sqlite", "mssql", "druid", "exasol"],
+    ["mysql", "sqlite", "mssql", "druid"],
     raises=com.OperationNotDefinedError,
 )
 @pytest.mark.notyet(["flink"], raises=com.OperationNotDefinedError)
@@ -1186,7 +1186,7 @@ def test_approx_median(alltypes):
 
 
 @pytest.mark.notimpl(
-    ["bigquery", "druid", "sqlite", "exasol"], raises=com.OperationNotDefinedError
+    ["bigquery", "druid", "sqlite"], raises=com.OperationNotDefinedError
 )
 @pytest.mark.notyet(
     ["impala", "mysql", "mssql", "druid", "trino"],