MM-43045: minimize JOIN Posts (#19934)

db/migrations/mysql/000081_threads_deleteat.down.sql

@@ -0,0 +1,14 @@
+SET @preparedStatement = (SELECT IF(
+    EXISTS(
+        SELECT 1 FROM INFORMATION_SCHEMA.STATISTICS
+        WHERE table_name = 'Threads'
+        AND table_schema = DATABASE()
+        AND column_name = 'DeleteAt'
+    ) > 0,
+    'ALTER TABLE Threads DROP COLUMN DeleteAt;',
+    'SELECT 1;'
+));
+
+PREPARE removeColumnIfExists FROM @preparedStatement;
+EXECUTE removeColumnIfExists;
+DEALLOCATE PREPARE removeColumnIfExists;

db/migrations/mysql/000081_threads_deleteat.up.sql

@@ -0,0 +1,19 @@
+SET @preparedStatement = (SELECT IF(
+    NOT EXISTS(
+        SELECT 1 FROM INFORMATION_SCHEMA.COLUMNS
+        WHERE table_name = 'Threads'
+        AND table_schema = DATABASE()
+        AND column_name = 'DeleteAt'
+    ),
+    'ALTER TABLE Threads ADD COLUMN DeleteAt bigint(20);',
+    'SELECT 1;'
+));
+
+PREPARE addColumnIfNotExists FROM @preparedStatement;
+EXECUTE addColumnIfNotExists;
+DEALLOCATE PREPARE addColumnIfNotExists;
+
+UPDATE Threads, Posts
+SET Threads.DeleteAt = Posts.DeleteAt
+WHERE Posts.Id = Threads.PostId
+AND Threads.DeleteAt IS NULL;

db/migrations/postgres/000081_threads_deleteat.down.sql

@@ -0,0 +1 @@
+ALTER TABLE threads DROP COLUMN IF EXISTS deleteat;

db/migrations/postgres/000081_threads_deleteat.up.sql

@@ -0,0 +1,2 @@
+ALTER TABLE threads ADD COLUMN IF NOT EXISTS deleteat bigint;
+UPDATE threads SET deleteat = posts.deleteat FROM posts WHERE threads.deleteat IS NULL AND posts.id = threads.postid;