date_trunc_postgres.sql

-- COUNT ITEMS BY DATE INTERVAL
SELECT
  DATE_TRUNC('hour', my_date_field), -- or second, minute, hour, day, week, month, year
  COUNT(id)
FROM my_table
WHERE my_field IS NOT NULL
GROUP BY 1
ORDER BY 2 DESC


-- OUT OF SYNC PRIMARY KEY SEQUENCE
 
-- Get the next PK in existing sequence
SELECT nextval('PK_index_name');
 
-- Re-synchronise the PK to the next id
SELECT setval('PK_index_name', COALESCE((SELECT MAX(PK_field_name)+1 FROM table_name), 1), false)