[BI-2995] Migrate parent ou ids in ou_level table to brapi ids

src/main/resources/db/migration/V006_001__migrate_parent_ou_ids.sql

@@ -0,0 +1,29 @@
+WITH
+    levels_and_parent_ou_bi_id AS (
+--      Find observation_unit_level codes that contain a key by checking for a space in the level code.
+--      Only other level codes that can exist are block/rep.
+--      Then extract the uuid from the level code, since program key is also contained there.
+        SELECT
+            id AS level_id,
+            substring(level_code FROM '^([^ ]+)') AS parent_bi_ou_id
+        FROM observation_unit_level
+        WHERE level_code LIKE '% %'
+    ),
+    ou_ids_matched_on_levels AS (
+--      Now match the bi-generated exref ou ids to ex refs ids, and keep observation_unit_level ids for matching in next part
+        SELECT
+            ou.id AS ou_id,
+            levels_and_parent_ou_bi_id.level_id
+        FROM observation_unit ou
+        JOIN observation_unit_external_references ouex ON ou.id = ouex.observation_unit_entity_id
+        JOIN external_reference ex ON ouex.external_references_id = ex.id
+        JOIN levels_and_parent_ou_bi_id ON ex.external_reference_id = levels_and_parent_ou_bi_id.parent_bi_ou_id
+    )
+UPDATE observation_unit_level
+SET level_code = regexp_replace(
+        observation_unit_level.level_code,
+        '^[^ ]+',
+        mol.ou_id::text
+)
+FROM ou_ids_matched_on_levels mol
+WHERE observation_unit_level.id = mol.level_id