Merge pull request #3004 from mikaelene/Snapshot_merge_WHEN_MATCHED

This changes makes the macro easier to read and workable on SQL Server

CHANGELOG.md

@@ -1,9 +1,11 @@
 ## dbt 0.19.0 (Release TBD)
 
 ### Under the hood
+- Rewrite macro for snapshot_merge_sql to make compatible with other SQL dialects ([#3003](https://github.com/fishtown-analytics/dbt/pull/3003)
 - Rewrite logic in `snapshot_check_strategy()` to make compatible with other SQL dialects ([#3000](https://github.com/fishtown-analytics/dbt/pull/3000), [#3001](https://github.com/fishtown-analytics/dbt/pull/3001))
 
 Contributors:
+- [@mikaelene](https://github.com/mikaelene) ([#3003](https://github.com/fishtown-analytics/dbt/pull/3003))
 - [@dbeatty10](https://github.com/dbeatty10) ([dbt-adapter-tests#10](https://github.com/fishtown-analytics/dbt-adapter-tests/pull/10))
 - [@swanderz](https://github.com/swanderz) ([#3000](https://github.com/fishtown-analytics/dbt/pull/3000))
 

core/dbt/include/global_project/macros/materializations/snapshot/snapshot_merge.sql

@@ -13,13 +13,7 @@
 
     when matched
      and DBT_INTERNAL_DEST.dbt_valid_to is null
-     and DBT_INTERNAL_SOURCE.dbt_change_type = 'update'
-        then update
-        set dbt_valid_to = DBT_INTERNAL_SOURCE.dbt_valid_to
-
-    when matched
-     and DBT_INTERNAL_DEST.dbt_valid_to is null
-     and DBT_INTERNAL_SOURCE.dbt_change_type = 'delete'
+     and DBT_INTERNAL_SOURCE.dbt_change_type in ('update', 'delete')
         then update
         set dbt_valid_to = DBT_INTERNAL_SOURCE.dbt_valid_to
 

plugins/postgres/dbt/include/postgres/macros/materializations/snapshot_merge.sql

@@ -6,14 +6,7 @@
     set dbt_valid_to = DBT_INTERNAL_SOURCE.dbt_valid_to
     from {{ source }} as DBT_INTERNAL_SOURCE
     where DBT_INTERNAL_SOURCE.dbt_scd_id::text = {{ target }}.dbt_scd_id::text
-      and DBT_INTERNAL_SOURCE.dbt_change_type::text = 'update'::text
-      and {{ target }}.dbt_valid_to is null;
-
-    update {{ target }}
-    set dbt_valid_to = DBT_INTERNAL_SOURCE.dbt_valid_to
-    from {{ source }} as DBT_INTERNAL_SOURCE
-    where DBT_INTERNAL_SOURCE.dbt_scd_id::text = {{ target }}.dbt_scd_id::text
-      and DBT_INTERNAL_SOURCE.dbt_change_type::text = 'delete'::text
+      and DBT_INTERNAL_SOURCE.dbt_change_type::text in ('update'::text, 'delete'::text)
       and {{ target }}.dbt_valid_to is null;
 
     insert into {{ target }} ({{ insert_cols_csv }})