refactor(api): make ibis.where and ibis.ifelse equivalent

ibis/backends/clickhouse/tests/test_select.py

@@ -221,7 +221,7 @@ def test_isnull_case_expr_rewrite_failure(db, alltypes):
 
     result = ibis.clickhouse.compile(reduction)
     expected = """\
-SELECT sum(CASE WHEN isNull(`string_col`) THEN 1 ELSE 0 END) AS `sum`
+SELECT sum(if(isNull(`string_col`), 1, 0)) AS `sum`
 FROM {0}.`functional_alltypes`"""
     assert result == expected.format(db.name)
 

ibis/backends/impala/tests/test_case_exprs.py

@@ -37,12 +37,12 @@ def test_isnull_1_0(table):
     expr = table.g.isnull().ifelse(1, 0)
 
     result = translate(expr)
-    expected = 'CASE WHEN `g` IS NULL THEN 1 ELSE 0 END'
+    expected = 'if(`g` IS NULL, 1, 0)'
     assert result == expected
 
     # inside some other function
     result = translate(expr.sum())
-    expected = 'sum(CASE WHEN `g` IS NULL THEN 1 ELSE 0 END)'
+    expected = 'sum(if(`g` IS NULL, 1, 0))'
     assert result == expected
 
 

ibis/backends/impala/tests/test_exprs.py

@@ -704,8 +704,7 @@ def test_where_with_timestamp():
     )
     result = ibis.impala.compile(expr)
     expected = """\
-SELECT `uuid`,
-       min(CASE WHEN `search_level` = 1 THEN `ts` ELSE NULL END) AS `min_date`
+SELECT `uuid`, min(if(`search_level` = 1, `ts`, NULL)) AS `min_date`
 FROM t
 GROUP BY 1"""
     assert result == expected
@@ -766,7 +765,7 @@ def test_nunique_where():
     t = ibis.table([('key', 'string'), ('value', 'double')], name='t0')
     expr = t.key.nunique(where=t.value >= 1.0)
     expected = """\
-SELECT count(DISTINCT CASE WHEN `value` >= 1.0 THEN `key` ELSE NULL END) AS `nunique`
+SELECT count(DISTINCT if(`value` >= 1.0, `key`, NULL)) AS `nunique`
 FROM t0"""  # noqa: E501
     result = ibis.impala.compile(expr)
     assert result == expected

ibis/backends/impala/tests/test_unary_builtins.py

@@ -161,11 +161,7 @@ def test_hash(table):
 def test_reduction_where(table, expr_fn, func_name):
     expr = expr_fn(table)
     result = translate(expr)
-    expected = (
-        f'{func_name}'
-        '(CASE WHEN `bigint_col` < 70 THEN `double_col` '
-        'ELSE NULL END)'
-    )
+    expected = f'{func_name}(if(`bigint_col` < 70, `double_col`, NULL))'
     assert result == expected
 
 

ibis/expr/api.py

@@ -681,31 +681,6 @@ def _add_methods(klass, method_table):
         setattr(klass, k, v)
 
 
-def where(
-    boolean_expr: ir.BooleanValue,
-    true_expr: ir.Value,
-    false_null_expr: ir.Value,
-) -> ir.Value:
-    """Return `true_expr` if `boolean_expr` is `True` else `false_null_expr`.
-
-    Parameters
-    ----------
-    boolean_expr
-        A boolean expression
-    true_expr
-        Value returned if `boolean_expr` is `True`
-    false_null_expr
-        Value returned if `boolean_expr` is `False` or `NULL`
-
-    Returns
-    -------
-    ir.Value
-        An expression
-    """
-    op = ops.Where(boolean_expr, true_expr, false_null_expr)
-    return op.to_expr()
-
-
 coalesce = ir.Value.coalesce
 greatest = ir.Value.greatest
 least = ir.Value.least
@@ -790,7 +765,7 @@ def category_label(
 geo_y_min = ir.GeoSpatialValue.y_min
 geo_unary_union = ir.GeoSpatialColumn.unary_union
 
-ifelse = ir.BooleanValue.ifelse
+where = ifelse = ir.BooleanValue.ifelse
 
 # ----------------------------------------------------------------------
 # Category API

ibis/expr/types/logical.py

@@ -41,12 +41,12 @@ def ifelse(
         SELECT CASE WHEN `is_person` THEN 'yes' ELSE 'no' END AS `tmp`
         FROM t
         """
-        import ibis
+        import ibis.expr.operations as ops
 
         # Result will be the result of promotion of true/false exprs. These
         # might be conflicting types; same type resolution as case expressions
         # must be used.
-        return ibis.case().when(self, true_expr).else_(false_expr).end()
+        return ops.Where(self, true_expr, false_expr).to_expr()
 
     def __and__(self, other: BooleanValue) -> BooleanValue:
         from ibis.expr import operations as ops

ibis/tests/sql/test_non_tabular_results.py

@@ -135,6 +135,6 @@ def test_isnull_case_expr_rewrite_failure(alltypes):
 
     result = Compiler.to_sql(reduction)
     expected = """\
-SELECT sum(CASE WHEN `g` IS NULL THEN 1 ELSE 0 END) AS `sum`
+SELECT sum(if(`g` IS NULL, 1, 0)) AS `sum`
 FROM alltypes"""
     assert result == expected