The display area of the chart editor shows any errors or warnings that apply to your chart.
Warnings tell you about a setting that you have made that has been ignored because it cannot be applied to the current chart. Warnings do not prevent the chart being drawn. They are shown for information. They are never shown when the chart is drawn on your website. The most common warnings are when axis overrides cannot be applied because they are inconsistent with the retrieved data. For example:
Warning: Y start [0] > first Y value in data [-6.25]
This warning is saying that you have asked for the chart's Y axis to start at the value zero, but Plotalot is ignoring your request because the lowest value in the relevant dataset is -6.25. You can read more about this in the section on Axis Options.
Errors prevent the chart being drawn. There are two main types of errors, Plotalot errors and SQL errors. This is a typical Plotalot error:
Error: For a Line graph, the first two columns must be numeric. Plot 2 column 1 [Date] is non-numeric, and column 2 [Value] is numeric
This error has occurred because the SQL query for plot 2 has returned the wrong column type(s) for the selected chart type. In this case, a line graph was selected, which requires two numeric columns, but the query returned a non-numeric column called Date and a numeric column called Value. The chart cannot be created until you correct the query to return the correct types of columns.
This is a typical SQL error:
Error: Plot 2: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server
version for the right syntax to use near 'DATE(CURDATE())) ORDER BY UnixDateTime' at line 1 [1064]
The SQL error code [1064] is included at the end of the error message. Sometimes it helps to Google the error number, for example, "SQL 1064".
The chart cannot be created until you correct the error.
Javascript errors are detected by your browser, and indicate a problem parsing the chart script. The most likely cause of a Javascript error is an error in your Extra Options.
A typical Javascript error looks like this:
Javascript error: Uncaught SyntaxError: Unexpected token }
Clear the Extra Options field, and if the error goes away, check your option syntax carefully.