The word chart, followed by the same naming convention above. *,, and : (which are not allowed in Microsoft Excel) are replaced with underscores ( _ ). Column names are truncated after 24 characters, and all occurrences of \, /, ?, The sheets are named with the column name. To determine the selectivity of a predicate over a string column, you should use the ESTIMATE or ESTIMATE_SOURCE functions.Īttempting to retrieve a histogram from string columns causes both sa_get_histogram and the Histogram utility to generate Or materialized view, execute a CREATE STATISTICS statement. In this case, you must create the statistics, and then run the Histogram utility again. In this case, the Histogram utility returns the message Histogram contains no data, aborting. Statistics (including histograms) may not be present for a table or materialized view, for example, if statistics were recentlyĭropped. The Histogram utility (dbhist) only works on Windows, and you must have Microsoft Excel 97 or later installed. The Histogram utility converts a histogram into a Microsoft Excel chart containing information about the selectivity of predicates. Histograms are stored in the ISYSCOLSTAT system table and can also be retrieved with the sa_get_histogram stored procedure.
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