Find consecutive days with gaps and islands, rank the longest streak per user, and define a current streak using the right business date.
Get the Second Row From a Table in SQL Server
To get the second row from a table, first decide what second means, because a table has no order until you give it one. This post builds a small demo and compares ROW_NUMBER, OFFSET and FETCH, and TOP inside TOP. It also covers every second row, the second row in each group, ties and the cost of each method.
Why Query Store Actual Operation Mode is Not Same as Requested? – Interview Question of the Week #248
Question: Why Query Store Actual Operation Mode is Not Same as Requested? Query Regression (poor performing queries, once working great)
Session Wait Stats: Find the Query Behind a Wait Type
Session wait stats tell you which session produced a wait type, and the input buffer tells you which query that session ran. This post shows how to see who waits right now, how to read the wait history of each session, and how to join them to the query text. It also explains the THREADPOOL wait.
Does GROUP BY Sort Results? Only ORDER BY Guarantees It
Does GROUP BY sort the rows it returns? No: only ORDER BY guarantees an order. This post builds a small demo, shows one GROUP BY query returning two different orders, and reads the plans that explain why.
SQL SERVER – Upgrade Error: The Specified Service Does Not Exist as an Installed Service
An upgrade from SQL Server 2008 R2 to 2014 failed after the product key step with: the specified service does not exist. Here is the fix.
SQL SERVER – Log Shipping Error: Only Members of the Sysadmin Fixed Server Role Can Perform This Operation
They have observed that Log Shipping Copy and Log Shipping Restore jobs have been failing with log shipping error. Let us fix them.