Graphs and charts are a useful visual way to view historical data - they make it easier to detect trends and get a big-picture view of data. All we need is timestamped data - table rows that are stamped with a specific date/time format, that can be used to group rows into time periods.
Time stamped data
In order to aggregate table data by time periods / ranges, we need a date/time column in the table we want to analyze. Appropriate types for such a column include
DATE, but we can also use string / numeric types for grouping data together if they contain some sort of date/time information - though those will be much less flexible than native date/time types.
I usually opt to go with the
TIMESTAMP format, for a couple of reasons - (more...)