fix #7413: inject sql header in query for show (#7568)

.changes/unreleased/Fixes-20230509-102932.yaml

@@ -0,0 +1,6 @@
+kind: Fixes
+body: inject sql header in query for show
+time: 2023-05-09T10:29:32.12947-07:00
+custom:
+  Author: aranke
+  Issue: "7413"

core/dbt/task/show.py

@@ -23,6 +23,11 @@ def execute(self, compiled_node, manifest):
         # Allow passing in -1 (or any negative number) to get all rows
         limit = None if self.config.args.limit < 0 else self.config.args.limit
 
+        if "sql_header" in compiled_node.unrendered_config:
+            compiled_node.compiled_code = (
+                compiled_node.unrendered_config["sql_header"] + compiled_node.compiled_code
+            )
+
         adapter_response, execute_result = self.adapter.execute(
             compiled_node.compiled_code, fetch=True, limit=limit
         )

tests/functional/show/fixtures.py

@@ -10,6 +10,14 @@
 from {{ ref('sample_model') }}
 """
 
+models__sql_header = """
+{% call set_sql_header(config) %}
+set session time zone 'Asia/Kolkata';
+{%- endcall %}
+select current_setting('timezone') as timezone
+"""
+
+
 schema_yml = """
 models:
   - name: sample_model

tests/functional/show/test_show.py

@@ -9,6 +9,7 @@
     models__second_model,
     models__ephemeral_model,
     schema_yml,
+    models__sql_header,
 )
 
 
@@ -19,6 +20,7 @@ def models(self):
             "sample_model.sql": models__sample_model,
             "second_model.sql": models__second_model,
             "ephemeral_model.sql": models__ephemeral_model,
+            "sql_header.sql": models__sql_header,
         }
 
     @pytest.fixture(scope="class")
@@ -105,6 +107,11 @@ def test_seed(self, project):
         (results, log_output) = run_dbt_and_capture(["show", "--select", "sample_seed"])
         assert "Previewing node 'sample_seed'" in log_output
 
+    def test_sql_header(self, project):
+        run_dbt(["build"])
+        (results, log_output) = run_dbt_and_capture(["show", "--select", "sql_header"])
+        assert "Asia/Kolkata" in log_output
+
 
 class TestShowModelVersions:
     @pytest.fixture(scope="class")