Compound assignment operators such as += and *= combine an operation with an assignment in T-SQL. The tests here run all eight operators on SQL Server 2025, and show how NULL, integer division, overflow, truncation and precedence change the result.
MAXDOP 1 in SQL Server: SQL in Sixty Seconds #008
MAXDOP 1 requests serial execution for one SQL Server query. I measured four variants of one query on SQL Server 2025, and the serial plan was the slowest in elapsed time with about the same CPU. The post shows the settings behind the hint and how to read the degree of parallelism a query actually used.
Table Variables and Transactions in SQL Server: SQL in Sixty Seconds #007
Table variables and transactions do not mix the way temporary tables do, because a ROLLBACK leaves the rows in a table variable. The tests here cover a full rollback, a savepoint, a failed statement and a logging pattern, all on SQL Server 2025.
SQL Server Indexing Basics: SQL in Sixty Seconds #006
SQL Server indexing basics start with the query you want to help. The tests here use a 200,000 row table to compare a scan, a plain index and a covering index, show when SQL Server ignores an index, and measure what three extra indexes cost on an insert.
T-SQL Errors and Reactions Demo: SQL in Sixty Seconds #005
This T-SQL errors and reactions demo follows episode #002 with queries you can run. It shows what a CATCH block can read, how severity is stored, how to log a failure and keep going, and why THROW keeps the original error while RAISERROR replaces it.
Leap Year in SQL Server: SQL in Sixty Seconds #004
To find a leap year in SQL Server, ask EOMONTH for the last day of February. I tested the method against the divisibility rule for every year from 1 to 9999 and found no disagreement. The post also shows an inline function, the errors for invalid years and a one-line TRY_CONVERT test.
Declare and Initialize Variables in SQL Server: SQL in Sixty Seconds #003
To declare and initialize variables in one statement, give each variable a type and a starting value in the same DECLARE. The tests here show the NULL default, a loop that does not reset an uninitialized variable, and the one character varchar trap on SQL Server 2025.