DISTINCT Option Examples | SQL SELECT Statements | Teradata Vantage - 17.05 - Examples - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - SQL Data Manipulation Language

Product
Advanced SQL Engine
Teradata Database
Release Number
17.05
Release Date
January 2021
Content Type
Programming Reference
Publication ID
B035-1146-175K
Language
English (United States)

Example: Simple Uses of DISTINCT

The following statement returns the number of unique job titles.

     SELECT COUNT(DISTINCT JobTitle)
     FROM …

The following statement lists the unique department numbers in the employee table.

     SELECT DISTINCT dept_no
     FROM employee;

The result returned is:

     dept_no
     -------
         100
         300
         500
         600
         700

Example: Using DISTINCT With Aggregates

The following statement uses the DISTINCT operator to eliminate duplicate values before applying SUM and AVG aggregate operators, respectively, to column x:

     SELECT SUM(DISTINCT x), AVG(DISTINCT x)
     FROM test_table;

You can only perform DISTINCT aggregations at the first, or highest level of aggregation if you specify subqueries.

Note that the result data type for a SUM operation on a DECIMAL(m,n) column is DECIMAL(p,n), as described in this table:

IF DBS Control field MaxDecimal is set to … AND … THEN p is …
  • 0
  • 15
m  15 15
15 < m  18 18
m > 18 38
18 m  18 18
m > 18 38
31 m  31 31
m > 31 38
38 m = any value 38