[LMS-1701] remove of redundant channel stacks

SVN: 17519

screening/source/sql/postgresql/migration/migration-005-006.sql

 -- Migration from 005 to 006
 
+
+-- Remove references to redundant channel stacks
+update acquired_images set channel_stack_id = mapping.new from (select cs.id as old, ucs.max_id as new from (select  max(id) as max_id,x,y,spot_id,ds_id from channel_stacks group by x,y,spot_id,ds_id) as ucs, channel_stacks cs where cs.x = ucs.x and cs.y = ucs.y and cs.spot_id = ucs.spot_id and cs.ds_id = ucs.ds_id and not cs.id = ucs.max_id) as mapping where mapping.old = channel_stack_id;
+
+-- Remove redundant channel stacks
+delete from channel_stacks where id not in (select  max(id) as max_id from channel_stacks group by x,y,spot_id,ds_id);
+
+
 ALTER TABLE CHANNELS ADD COLUMN CODE NAME;
 ALTER TABLE CHANNELS DROP CONSTRAINT CHANNELS_UK_1;
 ALTER TABLE CHANNELS DROP CONSTRAINT CHANNELS_UK_2;