Add support for sql as a header to create or replace

core/dbt/include/global_project/macros/adapters/common.sql

@@ -69,6 +69,10 @@
 {%- endmacro %}
 
 {% macro default__create_table_as(temporary, relation, sql) -%}
+  {%- set sql_header = config.get('sql_header', none) -%}
+
+  {{ sql_header if sql_header is not none }}
+
   create {% if temporary: -%}temporary{%- endif %} table
     {{ relation.include(database=(not temporary), schema=(not temporary)) }}
   as (
@@ -81,6 +85,10 @@
 {%- endmacro %}
 
 {% macro default__create_view_as(relation, sql) -%}
+  {%- set sql_header = config.get('sql_header', none) -%}
+
+  {{ sql_header if sql_header is not none }}
+
   create view {{ relation }} as (
     {{ sql }}
   );
@@ -269,3 +277,7 @@
 
     {% do return(tmp_relation) %}
 {% endmacro %}
+
+{% macro set_sql_header(config) -%}
+  {{ config.set('sql_header', caller()) }}
+{%- endmacro %}

core/dbt/source_config.py

@@ -16,7 +16,7 @@ class SourceConfig:
         'unique_key',
         'database',
         'severity',
-
+        'sql_header',
         'incremental_strategy',
 
         # snapshots

plugins/bigquery/dbt/include/bigquery/macros/adapters.sql

@@ -61,6 +61,10 @@
   {%- set raw_persist_docs = config.get('persist_docs', {}) -%}
   {%- set raw_kms_key_name = config.get('kms_key_name', none) -%}
   {%- set raw_labels = config.get('labels', []) -%}
+  {%- set sql_header = config.get('sql_header', none) -%}
+
+  {{ sql_header if sql_header is not none }}
+
   create or replace table {{ relation }}
   {{ partition_by(raw_partition_by) }}
   {{ cluster_by(raw_cluster_by) }}
@@ -76,6 +80,9 @@
 {% macro bigquery__create_view_as(relation, sql) -%}
   {%- set raw_persist_docs = config.get('persist_docs', {}) -%}
   {%- set raw_labels = config.get('labels', []) -%}
+  {%- set sql_header = config.get('sql_header', none) -%}
+
+  {{ sql_header if sql_header is not none }}
 
   create or replace view {{ relation }}
   {{ bigquery_table_options(persist_docs=raw_persist_docs, temporary=false, labels=raw_labels) }}

plugins/postgres/dbt/include/postgres/macros/adapters.sql

@@ -1,5 +1,8 @@
 {% macro postgres__create_table_as(temporary, relation, sql) -%}
   {%- set unlogged = config.get('unlogged', default=false) -%}
+  {%- set sql_header = config.get('sql_header', none) -%}
+
+  {{ sql_header if sql_header is not none }}
 
   create {% if temporary -%}
     temporary

plugins/redshift/dbt/include/redshift/macros/adapters.sql

@@ -37,6 +37,9 @@
   {%- set _sort = config.get(
           'sort',
           validator=validation.any[list, basestring]) -%}
+  {%- set sql_header = config.get('sql_header', none) -%}
+
+  {{ sql_header if sql_header is not none }}
 
   create {% if temporary -%}temporary{%- endif %} table
     {{ relation.include(database=(not temporary), schema=(not temporary)) }}
@@ -51,6 +54,9 @@
 {% macro redshift__create_view_as(relation, sql) -%}
 
   {% set bind_qualifier = '' if config.get('bind', default=True) else 'with no schema binding' %}
+  {%- set sql_header = config.get('sql_header', none) -%}
+
+  {{ sql_header if sql_header is not none }}
 
   create view {{ relation }} as (
     {{ sql }}

plugins/snowflake/dbt/include/snowflake/macros/adapters.sql

@@ -11,6 +11,9 @@
   {% else %}
     {%- set cluster_by_string = none -%}
   {%- endif -%}
+  {%- set sql_header = config.get('sql_header', none) -%}
+
+  {{ sql_header if sql_header is not none }}
 
       create or replace {% if temporary -%}
         temporary
@@ -38,6 +41,9 @@
 {% macro snowflake__create_view_as(relation, sql) -%}
   {%- set secure = config.get('secure', default=false) -%}
   {%- set copy_grants = config.get('copy_grants', default=false) -%}
+  {%- set sql_header = config.get('sql_header', none) -%}
+
+  {{ sql_header if sql_header is not none }}
   create or replace {% if secure -%}
     secure
   {%- endif %} view {{ relation }} {% if copy_grants -%} copy grants {%- endif %} as (

test/integration/022_bigquery_test/models/sql_header_model.sql

@@ -0,0 +1,14 @@
+{{ config(materialized="table") }}
+
+{# This will fail if it is not extracted correctly #}
+{% call set_sql_header(config) %}
+  	CREATE TEMPORARY FUNCTION a_to_b(str STRING)
+	RETURNS STRING AS (
+	  CASE
+	  WHEN LOWER(str) = 'a' THEN 'b'
+	  ELSE str
+	  END
+	);
+{% endcall %}
+
+select a_to_b(dupe) as dupe from {{ ref('view_model') }}

test/integration/022_bigquery_test/test_simple_bigquery_view.py

@@ -53,7 +53,7 @@ def test__bigquery_simple_run(self):
         self.run_dbt(['seed', '--full-refresh'])
         results = self.run_dbt()
         # Bump expected number of results when adding new model
-        self.assertEqual(len(results), 7)
+        self.assertEqual(len(results), 8)
         self.assert_nondupes_pass()
 
 
@@ -64,7 +64,7 @@ class TestUnderscoreBigQueryRun(TestBaseBigQueryRun):
     def test_bigquery_run_twice(self):
         self.run_dbt(['seed'])
         results = self.run_dbt()
-        self.assertEqual(len(results), 7)
+        self.assertEqual(len(results), 8)
         results = self.run_dbt()
-        self.assertEqual(len(results), 7)
+        self.assertEqual(len(results), 8)
         self.assert_nondupes_pass()