A page's daily view counter — every hit either creates a row with one or increments the existing one. Doing "read → check → write" as separate statements is unsafe: concurrent hits lose increments. The table counters(id, count) is empty. Implement insert-or-update: try to insert the row with id 1 and counter 1; on a conflict by id the existing counter goes up by one. Run the command five times — after five runs the value should be 5.