ALTER TABLE … DROP PRIMARY KEY is MySQL syntax and fails in SQL Server with Msg 156. Here is how to drop primary key constraint the SQL Server way.
SQL SERVER – Questions and Answers with Database Administrators
While hiring Database Administrators and senior developers for a large project, we discussed many interesting questions. Here are some, with my own views.
SQL SERVER – Find Last Date Time Updated for Any Table
Want the last date time a table was updated without an UpdatedDate column? The sys.dm_db_index_usage_stats DMV shows it. A quick demo on AdventureWorks.
INTERSECT: Return Shared Values Once
INTERSECT returns distinct shared rows, including shared NULL. Compare it with an equality join that preserves matching-pair multiplicity.
PI: Choose the Precision of a Circle Calculation
PI provides an approximate circle constant. This example keeps radius, circumference and two area calculations together to show when a chosen decimal conversion occurs.
SQL SERVER – Add or Remove Identity Property on Column
There is no direct T-SQL to add or remove the identity property on an existing column. Imran Mohammed shows how SSMS does it and what happens behind it.
geometry STIntersection: Return the Shared Shape
geometry STIntersection returns the shared shape rather than only an intersection flag. I inspect its type and emptiness alongside its area. A shared edge has zero area but still contains points.