Enable setting dbt_valid_to snapshot column to new setting dbt_valid_to_current

.changes/unreleased/Features-20240927-133708.yaml

@@ -0,0 +1,6 @@
+kind: Features
+body: Enable setting current value of dbt_valid_to
+time: 2024-09-27T13:37:08.808843-04:00
+custom:
+  Author: gshank
+  Issue: "151"

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

@@ -9,7 +9,12 @@
     from {{ source }} as DBT_INTERNAL_SOURCE
     where DBT_INTERNAL_SOURCE.{{ columns.dbt_scd_id }}::text = {{ target }}.{{ columns.dbt_scd_id }}::text
       and DBT_INTERNAL_SOURCE.dbt_change_type::text in ('update'::text, 'delete'::text)
-      and {{ target }}.{{ columns.dbt_valid_to }} is null;
+      {% if config.get("dbt_valid_to_current") %}
+        and ({{ target }}.{{ columns.dbt_valid_to }} = {{ config.get('dbt_valid_to_current') }} or {{ target }}.{{ columns.dbt_valid_to }} is null);
+      {% else %}
+        and {{ target }}.{{ columns.dbt_valid_to }} is null;
+      {% endif %}
+
 
     insert into {{ target }} ({{ insert_cols_csv }})
     select {% for column in insert_cols -%}