Propagating The Last Non-Null Value With T-SQL

Kevin Feasel

2018-08-08

T-SQL

Tomaz Kastrun shows a great use of window functions in T-SQL:

So you have NULL values in your SQL Server table and you want to populate those NULL values with the last non-NULL value, based on a particular order. Once you have only one NULL values encapsulated between two populated values, there are quick and fast solutions. But what if you find a larger gap of NULL values and you want to populate these values as well?

Click through for a partial solution, followed by the real solution.

Related Posts

Converting Binary To Hex With T-SQL

Dave Mason uses STRING_SPLIT to convert binary values to their hex equivalents: I started pondering it for a bit and began to wonder if I could use the new for SQL Server 2016 STRING_SPLIT function to convert a binary string to decimal. The thought process was to split the string into rows of CHAR(1) values, along with an in-string character […]

Read More

Faster Scalar Functions In SQL Server 2019

Brent Ozar looks at improvements the SQL Server team has made to scalar functions in 2019: My database has to be in 2019 compat mode to enable Froid, the function-inlining magic. Run the same query again, and the metrics are wildly different: Runtime: 4 seconds CPU time: 4 seconds Logical reads: 3,247,991 (which still sounds bad, […]

Read More

Categories

August 2018
MTWTFSS
« Jul Sep »
 12345
6789101112
13141516171819
20212223242526
2728293031