feat: support JSON literal values (#11728)

## Description of changes

Adds support for JSON literals to SQLGlot-based backends.

## Issues closed

* Resolves #11727

---------

Co-authored-by: Phillip Cloud <417981+cpcloud@users.noreply.github.com>

Author: tswast

ibis/backends/sql/compilers/base.py

@@ -792,6 +792,8 @@ def visit_DefaultLiteral(self, op, *, value, dtype):
             )
         elif dtype.is_boolean():
             return sge.Boolean(this=bool(value))
+        elif dtype.is_json():
+            return sge.JSON(this=sge.convert(str(value)))
         elif dtype.is_string():
             return sge.convert(value)
         elif dtype.is_inet() or dtype.is_macaddr():

ibis/backends/tests/test_json.py

@@ -7,6 +7,8 @@
 import pytest
 from packaging.version import parse as vparse
 
+import ibis
+import ibis.expr.datatypes as dt
 import ibis.expr.types as ir
 from ibis.backends.tests.conftest import NO_JSON_SUPPORT_MARKS
 from ibis.backends.tests.errors import PySparkPythonException
@@ -62,6 +64,21 @@ def test_json_getitem_array(json_t):
     assert result == expected
 
 
+@pytest.mark.notimpl(["polars"])
+@pytest.mark.notyet(
+    ["sqlite", "mysql", "pyspark"],
+    reason="Syntax error near 'AS'",
+)
+@pytest.mark.notyet(
+    ["flink"],
+    reason="Expecting alias, found character literal",
+)
+def test_json_literal(con):
+    expr = ibis.literal('{"scale": 100}', dt.json).name("some_literal")
+    result = con.execute(expr)
+    assert result == {"scale": 100}
+
+
 @pytest.mark.notimpl(["mysql", "risingwave"])
 @pytest.mark.notyet(["bigquery", "sqlite"], reason="doesn't support maps")
 @pytest.mark.notyet(["postgres"], reason="only supports map<string, string>")