Question

I have a table defined like this:

Column:  Version     Message
Type:    varchar(20) varchar(100)
----------------------------------
Row 1:    2.2.6       Message 1
Row 2:    2.2.7       Message 2
Row 3:    2.2.12      Message 3
Row 4:    2.3.9       Message 4
Row 5:    2.3.15      Message 5

I want to write a T-Sql query that will get message for the MAX version number, where the “Version” column represents a software version number. I.e., 2.2.12 is greater than 2.2.7, and 2.3.15 is greater than 2.3.9, etc. Unfortunately, I can’t think of an easy way to do that without using CHARINDEX or some complicated other split-like logic. Running this query:

SELECT MAX(Version) FROM my_table

will yield the erroneous result:

2.3.9

When it should really be 2.3.15. Any bright ideas that don’t get too complex?

Answer 1

One solution would be to use a table-valued split function to split the versions into rows and then combine them back into columns so that you can do something like:

Select TOP 1 Major, Minor, Build
From ( ...derived crosstab query )
Order By Major Desc, Minor Desc, Build Desc

Actually, another way is to use the PARSENAME function which was meant to split object names:

Select TOP 1 Version
From Table
Order By Cast(Parsename( Z.Version , 3 ) As Int) Desc
    , Cast(Parsename( Z.Version , 2 ) As Int) Desc
    , Cast(Parsename( Z.Version , 1 ) As Int) Desc