Added equals macro that handles null value comparison

.changes/unreleased/Under the Hood-20241217-110536.yaml

@@ -0,0 +1,6 @@
+kind: Under the Hood
+body: Added new equals macro that handles null value checks in sql
+time: 2024-12-17T11:05:36.363421+02:00
+custom:
+    Author: adrianburusdbt
+    Issue: "159"

dbt-tests-adapter/dbt/tests/adapter/incremental/test_incremental_unique_id.py

@@ -240,6 +240,8 @@
 select 'NY','New York','Manhattan','2021-04-01'
 union all
 select 'PA','Philadelphia','Philadelphia','2021-05-21'
+union all
+select 'CO','Denver',null,'2021-06-18'
 
 """
 
@@ -265,6 +267,8 @@
 select 'NY','New York','Manhattan','2021-04-01'
 union all
 select 'PA','Philadelphia','Philadelphia','2021-05-21'
+union all
+select 'CO','Denver',null,'2021-06-18'
 
 """
 
@@ -288,6 +292,7 @@
 NY,Kings,Brooklyn,2021-04-02
 NY,New York,Manhattan,2021-04-01
 PA,Philadelphia,Philadelphia,2021-05-21
+CO,Denver,,2021-06-18
 """
 
 seeds__add_new_rows_sql = """
@@ -439,7 +444,7 @@ def fail_to_build_inc_missing_unique_key_column(self, incremental_model_name):
     def test__no_unique_keys(self, project):
         """with no unique keys, seed and model should match"""
 
-        expected_fields = self.get_expected_fields(relation="seed", seed_rows=8)
+        expected_fields = self.get_expected_fields(relation="seed", seed_rows=9)
         test_case_fields = self.get_test_fields(
             project, seed="seed", incremental_model="no_unique_key", update_sql_file="add_new_rows"
         )
@@ -449,7 +454,7 @@ def test__no_unique_keys(self, project):
     def test__empty_str_unique_key(self, project):
         """with empty string for unique key, seed and model should match"""
 
-        expected_fields = self.get_expected_fields(relation="seed", seed_rows=8)
+        expected_fields = self.get_expected_fields(relation="seed", seed_rows=9)
         test_case_fields = self.get_test_fields(
             project,
             seed="seed",
@@ -462,7 +467,7 @@ def test__one_unique_key(self, project):
         """with one unique key, model will overwrite existing row"""
 
         expected_fields = self.get_expected_fields(
-            relation="one_str__overwrite", seed_rows=7, opt_model_count=1
+            relation="one_str__overwrite", seed_rows=8, opt_model_count=1
         )
         test_case_fields = self.get_test_fields(
             project,
@@ -487,7 +492,7 @@ def test__bad_unique_key(self, project):
     def test__empty_unique_key_list(self, project):
         """with no unique keys, seed and model should match"""
 
-        expected_fields = self.get_expected_fields(relation="seed", seed_rows=8)
+        expected_fields = self.get_expected_fields(relation="seed", seed_rows=9)
         test_case_fields = self.get_test_fields(
             project,
             seed="seed",
@@ -500,7 +505,7 @@ def test__unary_unique_key_list(self, project):
         """with one unique key, model will overwrite existing row"""
 
         expected_fields = self.get_expected_fields(
-            relation="unique_key_list__inplace_overwrite", seed_rows=7, opt_model_count=1
+            relation="unique_key_list__inplace_overwrite", seed_rows=8, opt_model_count=1
         )
         test_case_fields = self.get_test_fields(
             project,
@@ -515,7 +520,7 @@ def test__duplicated_unary_unique_key_list(self, project):
         """with two of the same unique key, model will overwrite existing row"""
 
         expected_fields = self.get_expected_fields(
-            relation="unique_key_list__inplace_overwrite", seed_rows=7, opt_model_count=1
+            relation="unique_key_list__inplace_overwrite", seed_rows=8, opt_model_count=1
         )
         test_case_fields = self.get_test_fields(
             project,
@@ -530,7 +535,7 @@ def test__trinary_unique_key_list(self, project):
         """with three unique keys, model will overwrite existing row"""
 
         expected_fields = self.get_expected_fields(
-            relation="unique_key_list__inplace_overwrite", seed_rows=7, opt_model_count=1
+            relation="unique_key_list__inplace_overwrite", seed_rows=8, opt_model_count=1
         )
         test_case_fields = self.get_test_fields(
             project,
@@ -545,7 +550,7 @@ def test__trinary_unique_key_list_no_update(self, project):
         """even with three unique keys, adding distinct rows to seed does not
         cause seed and model to diverge"""
 
-        expected_fields = self.get_expected_fields(relation="seed", seed_rows=8)
+        expected_fields = self.get_expected_fields(relation="seed", seed_rows=9)
         test_case_fields = self.get_test_fields(
             project,
             seed="seed",

dbt-tests-adapter/dbt/tests/adapter/utils/base_utils.py

@@ -1,16 +1,6 @@
 import pytest
 from dbt.tests.util import run_dbt
 
-
-macros__equals_sql = """
-{% macro equals(expr1, expr2) -%}
-case when (({{ expr1 }} = {{ expr2 }}) or ({{ expr1 }} is null and {{ expr2 }} is null))
-    then 0
-    else 1
-end = 0
-{% endmacro %}
-"""
-
 macros__test_assert_equal_sql = """
 {% test assert_equal(model, actual, expected) %}
 select * from {{ model }}
@@ -33,7 +23,6 @@ class BaseUtils:
     @pytest.fixture(scope="class")
     def macros(self):
         return {
-            "equals.sql": macros__equals_sql,
             "test_assert_equal.sql": macros__test_assert_equal_sql,
             "replace_empty.sql": macros__replace_empty_sql,
         }

dbt-tests-adapter/dbt/tests/adapter/utils/test_equals.py

@@ -1,16 +1,10 @@
 import pytest
 
-from dbt.tests.adapter.utils import base_utils, fixture_equals
+from dbt.tests.adapter.utils import fixture_equals
 from dbt.tests.util import relation_from_name, run_dbt
 
 
 class BaseEquals:
-    @pytest.fixture(scope="class")
-    def macros(self):
-        return {
-            "equals.sql": base_utils.macros__equals_sql,
-        }
-
     @pytest.fixture(scope="class")
     def seeds(self):
         return {

dbt/include/global_project/macros/materializations/models/incremental/merge.sql

@@ -21,8 +21,14 @@
                 {% do predicates.append(this_key_match) %}
             {% endfor %}
         {% else %}
+            {% set source_unique_key %}
+                DBT_INTERNAL_SOURCE.{{ unique_key }}
+            {% endset %}
+            {% set target_unique_key %}
+                DBT_INTERNAL_DEST.{{ unique_key }}
+            {% endset %}
             {% set unique_key_match %}
-                DBT_INTERNAL_SOURCE.{{ unique_key }} = DBT_INTERNAL_DEST.{{ unique_key }}
+                {{ equals(source_unique_key, target_unique_key) }}
             {% endset %}
             {% do predicates.append(unique_key_match) %}
         {% endif %}
@@ -62,11 +68,18 @@
 
     {% if unique_key %}
         {% if unique_key is sequence and unique_key is not string %}
-            delete from {{target }}
+            delete from {{ target }}
             using {{ source }}
             where (
                 {% for key in unique_key %}
-                    {{ source }}.{{ key }} = {{ target }}.{{ key }}
+                    {% set source_unique_key %}
+                        {{ source }}.{{ key }}
+                    {% endset %}
+                    {% set target_unique_key %}
+                        {{ target }}.{{ key }}
+                    {% endset %}
+
+                    {{ equals(source_unique_key, target_unique_key) }}
                     {{ "and " if not loop.last}}
                 {% endfor %}
                 {% if incremental_predicates %}

dbt/include/global_project/macros/materializations/snapshots/helpers.sql

@@ -53,8 +53,14 @@
         from {{ target_relation }}
         where
             {% if config.get('dbt_valid_to_current') %}
-               {# Check for either dbt_valid_to_current OR null, in order to correctly update records with nulls #}
-               ( {{ columns.dbt_valid_to }} = {{ config.get('dbt_valid_to_current') }} or {{ columns.dbt_valid_to }} is null)
+                {% set source_unique_key %}
+                    columns.dbt_valid_to
+                {% endset %}
+                {% set target_unique_key %}
+                    config.get('dbt_valid_to_current')
+                {% endset %}
+
+               {{ equals(source_unique_key, target_unique_key) }}
             {% else %}
                 {{ columns.dbt_valid_to }} is null
             {% endif %}
@@ -276,7 +282,14 @@
 {% macro unique_key_join_on(unique_key, identifier, from_identifier) %}
     {% if unique_key | is_list %}
         {% for key in unique_key %}
-            {{ identifier }}.dbt_unique_key_{{ loop.index }} = {{ from_identifier }}.dbt_unique_key_{{ loop.index }}
+            {% set source_unique_key %}
+                {{ identifier }}.dbt_unique_key_{{ loop.index }}
+            {% endset %}
+            {% set target_unique_key %}
+                {{ from_identifier }}.dbt_unique_key_{{ loop.index }}
+            {% endset %}
+
+            {{ equals(source_unique_key, target_unique_key) }}
             {%- if not loop.last %} and {%- endif %}
         {% endfor %}
     {% else %}

dbt/include/global_project/macros/materializations/snapshots/snapshot_merge.sql

@@ -15,8 +15,14 @@
 
     when matched
      {% if config.get("dbt_valid_to_current") %}
-       and (DBT_INTERNAL_DEST.{{ columns.dbt_valid_to }} = {{ config.get('dbt_valid_to_current') }} or
-            DBT_INTERNAL_DEST.{{ columns.dbt_valid_to }} is null)
+        {% set source_unique_key %}
+            DBT_INTERNAL_DEST.{{ columns.dbt_valid_to }}
+        {% endset %}
+        {% set target_unique_key %}
+            {{ config.get('dbt_valid_to_current') }}
+        {% endset %}
+       and {{ equals(source_unique_key, target_unique_key) }}
+
      {% else %}
        and DBT_INTERNAL_DEST.{{ columns.dbt_valid_to }} is null
      {% endif %}

dbt/include/global_project/macros/utils/equals.sql

@@ -0,0 +1,12 @@
+{% macro equals(expr1, expr2) %}
+    {{ return(adapter.dispatch('equals', 'dbt') (expr1, expr2)) }}
+{%- endmacro %}
+
+{% macro default__equals(expr1, expr2) -%}
+
+    case when (({{ expr1 }} = {{ expr2 }}) or ({{ expr1 }} is null and {{ expr2 }} is null))
+        then 0
+        else 1
+    end = 0
+
+{% endmacro %}