Fear No SQL
After completing my article about skewness of a sample for Joel Kallman Day I decided I could do one more and write up the related functionality for skewness of a population. Like skewness of a sample, the purpose of the function is to indicate the degree and direction of asymmetry in a data distribution. Like…
Several years ago I needed to calculate the skewness of some data. That is, an indication of how asymmetric points are within a distribution. Unfortunately, I found there was no native feature to do this within SQL. So I wrote my own with the Oracle Data Cartridge Interface (ODCI.) Using ODCI you can create your…
An INTERVAL YEAR TO MONTH, can have up to 9 digits of year precision. By default, a column or pl/sql variable will have 2 digits. The month portion of the interval is always limited to 2 digits. The year limits can be changed by specifying (0-9) in the declaration. select INTERVAL ‘123-06’ YEAR(3) TO MONTH…
An INTERVAL DAY TO SECOND, can have up to 9 digits of sub-second precision (nanoseconds.) By default, a column or pl/sql variable will have 6 digits (microseconds.) In addition to the subsecond precision, a default INTERVAL DAY TO SECOND will also be limited to 2 digits in the day counter. These limits can be changed…
Some data is more easily absorbed in visual form. Trending and relative comparisons in particular can often be digested at a glance when presented as a line or bar chart. While SQL itself doesn’t have any graphing capabilities; using some of the Unicode symbol characters it is possible to create simple charts within a text…
Previously, I’ve shown how to use a user-defined aggregate to process numeric values; but they can be used for text as well. Recently I was tasked with importing some denormalized text data and aggregating into a consistent form. The source data consisted of many rows holding identifiers, multiple comma-separated values (CSV,) and several other fields.…
A common occurrence in sql is to aggregate text values into a larger, delimited value. It can also occur that you have a delimited value and you want treat it as a collection to pull data out of it process each of the sub-values. Oracle has a built-in function LISTAGG to aggregate text values into…