To validate a date with regex in SQL Server 2025, pair REGEXP_LIKE with TRY_CONVERT. The tests here show impossible dates that pass a strict pattern, spellings that convert but break the format, and how to enforce both checks with a constraint.
Removing Repeated Characters From a String With GENERATE_SERIES
Remove repeated characters with GENERATE_SERIES, ROW_NUMBER, and ordered STRING_AGG, then benchmark a SQL Server 2019 fallback.
Concat Strings in SQL Server: SQL in Sixty Seconds #035
To concat strings in SQL Server, use the + operator or the CONCAT function. The tests here show what each one does with NULL, numbers and dates, how the 8000 character limit cuts a result, and when CONCAT_WS or STRING_AGG is the better tool.
STRING_AGG Limits: The 8,000 Byte Error, Ordering and Duplicates
Fix STRING_AGG 8,000-byte limits, enforce ordering, remove duplicates before aggregation, and compare its timing with XML.
Display Datetime in a Specific Format: CONVERT and FORMAT
To display datetime in a specific format, use CONVERT with a style number or FORMAT with a pattern. This post tests both on a fixed value, shows the lowercase pattern mistake, measures how much slower FORMAT is, and explains why parsing text dates needs a style.
SQL SERVER – Order By Numeric Values Formatted as String
A column holds alphanumeric values that start with a number, and ORDER BY sorts them as text. Here is how to sort the rows by the Numeric part instead.
SQL SERVER – Find First Non-Numeric Character from String
No built-in function finds the first non-numeric character in a string, so I use PATINDEX. Here is a quick script with sample data you can try.