Chapter 3 DBMS Reference Guide

SqlStatistics

SQL Query to reverse engineer column and table statistics.

Example

In Sybase Adaptive Server Enterprise 15.0:

[%ISLONGDTTP%?{ AverageLength }
select [%ISLONGDTTP%?[%ISSTRDTTP%?avg(char_length(%COLUMN%)):avg(datalength(%COLUMN%))]:null] as average_length
from [%QUALIFIER%]%TABLE%
:{ NullValuesRate, DistinctValues, AverageLength }
select
[%ISMAND%?null:(count(*) - count(%COLUMN%)) * 100 / count(*)]  as null_values,
[%ISMAND%?null:count(distinct %COLUMN%)]  as distinct_values,
[%ISVARDTTP%?[%ISSTRDTTP%?avg(char_length(%COLUMN%)):avg(datalength(%COLUMN%))]:null] as average_length
from [%QUALIFIER%]%TABLE%]

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