Find most used data type in Azure SQL Database

The query below returns data types used in a database ordered by the number of their occurrence.

Query

select t.name as data_type,
    count(*) as [columns],
    cast(100.0 * count(*) /
    (select count(*) from sys.tables as tab inner join
        sys.columns as col on tab.object_id = col.object_id)
            as numeric(36, 1)) as percent_columns,
      count(distinct tab.object_id) as [tables],
      cast(100.0 * count(distinct tab.object_id) /
      (select count(*) from sys.tables) as numeric(36, 1)) as percent_tables
  from sys.tables as tab
       inner join sys.columns as col
        on tab.object_id = col.object_id
       left join sys.types as t
        on col.user_type_id = t.user_type_id
group by t.name
order by count(*) desc

Columns

  • data_type - built-in or user data type without length or precision, e.g. int, varchar or date
  • columns - number of columns in a database with this data type
  • percent_columns - percentage of columns with this data type. Rows add up to 100%
  • tables - number of tables in a database with this data type
  • percent_tables - percentage of tables that have columns with this data type

Rows

  • One row: represents one data type
  • Scope of rows: all data types used in a database
  • Ordered by: number of columns in descending order

Sample results

These results show the data types used in the AdventureWorksLT database. As you can see, the most popular data type is int - used in 29 columns representing 24.8% of all columns in 15 tables (representing 93.8% of all tables).

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