feat(mysql): move string join impl up to alchemy for mysql

ibis/backends/base/sql/alchemy/registry.py

@@ -434,6 +434,11 @@ def _sort_key(t, expr):
     return sort_direction(t.translate(by))
 
 
+def _string_join(t, expr):
+    sep, elements = expr.op().args
+    return sa.func.concat_ws(t.translate(sep), *map(t.translate, elements))
+
+
 sqlalchemy_operation_registry: Dict[Any, Any] = {
     ops.And: fixed_arity(sql.and_, 2),
     ops.Or: fixed_arity(sql.or_, 2),
@@ -482,6 +487,7 @@ def _sort_key(t, expr):
     ops.Uppercase: unary(sa.func.upper),
     ops.StringAscii: unary(sa.func.ascii),
     ops.StringLength: unary(sa.func.length),
+    ops.StringJoin: _string_join,
     ops.StringReplace: fixed_arity(sa.func.replace, 3),
     ops.StringSQLLike: functools.partial(_string_like, "like"),
     ops.StringSQLILike: functools.partial(_string_like, "ilike"),

ibis/backends/postgres/registry.py

@@ -596,11 +596,6 @@ def _array_slice(t, expr):
     return sa_arg[sa_start + 1 : sa_stop]
 
 
-def _string_join(t, expr):
-    sep, elements = expr.op().args
-    return sa.func.concat_ws(t.translate(sep), *map(t.translate, elements))
-
-
 def _literal(t, expr):
     dtype = expr.type()
     op = expr.op()
@@ -669,7 +664,6 @@ def _day_of_week_name(t, expr):
             ),
             2,
         ),
-        ops.StringJoin: _string_join,
         ops.FindInSet: _find_in_set,
         # math
         ops.Log: _log,

ibis/backends/tests/test_string.py

@@ -262,7 +262,24 @@ def test_string_col_is_unicode(backend, alltypes, df):
             lambda t: ibis.literal('-').join(['a', t.string_col, 'c']),
             lambda t: 'a-' + t.string_col + '-c',
             id='join',
-            marks=pytest.mark.notimpl(["datafusion", "mysql", "sqlite"]),
+        ),
+        param(
+            lambda t: t.string_col + t.date_string_col,
+            lambda t: t.string_col + t.date_string_col,
+            id='concat_columns',
+            marks=pytest.mark.notimpl(["datafusion", "clickhouse"]),
+        ),
+        param(
+            lambda t: t.string_col + 'a',
+            lambda t: t.string_col + 'a',
+            id='concat_column_scalar',
+            marks=pytest.mark.notimpl(["datafusion", "clickhouse"]),
+        ),
+        param(
+            lambda t: 'a' + t.string_col,
+            lambda t: 'a' + t.string_col,
+            id='concat_scalar_column',
+            marks=pytest.mark.notimpl(["datafusion", "clickhouse"]),
         ),
     ],
 )