UNPIVOT

Today I ran into an interesting question on the forums at SQLServerCentral and I decided to share the solution I provided, because it was fun to code and, hopefully, useful for some of you. Many experienced T-SQL coders make use of FOR XML PATH(‘’) to build concatenated strings from multiple rows. It’s a nice technique and pretty simple to use. For instance, if you want to create a list of databases in a single concatenated string, you can run this statement: [Read More]

Some bugs in Oracle’s code are really surprising. Whenever I run into this kind of issue, I can’t help but wonder how nobody else noticed it before. Some days ago I was querying AWR data from DBA_HIST_SYSMETRIC_SUMMARY and I wanted to turn the columns AVERAGE, MAXVAL and MINVAL into rows, in order to fit this result set into a performance graphing application that expects input data formatted as {TimeStamp, SeriesName, Value}. [Read More]