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Find out the ASCII-Code of a Character in Teradata SQL

Teradata SQL

If you ever had the need to find out the ASCII-Code of a character, you will know that no function in Teradata SQL exists to solve this problem.

Here is a query workaround which solves this issue. What below SQL statement does is the following:

The CHAR2HEXINT Teradata SQL function returns a hexadecimal value; we need to convert it into the decimal number system. Conversion is done by taking the first part of the returned hexadecimal value multiplied by 16 and adding the second part of the hexadecimal value.

 

SELECT
CASE SUBSTRING(CHAR2HEXINT(‘B’) FROM 3 FOR 1)
WHEN ‘0’ THEN 0
WHEN ‘1’ THEN 1
WHEN ‘2’ THEN 2
WHEN ‘3’ THEN 3
WHEN ‘4’ THEN 4
WHEN ‘5’ THEN 5
WHEN ‘6’ THEN 6
WHEN ‘7’ THEN 7
WHEN ‘8’ THEN 8
WHEN ‘9’ THEN 9
WHEN ‘A’ THEN 10
WHEN ‘B’ THEN 11
WHEN ‘C’ THEN 12
WHEN ‘D’ THEN 13
WHEN ‘E’ THEN 14
WHEN ‘F’ THEN 15
END * 16 +
CASE SUBSTRING(CHAR2HEXINT(‘B’) FROM 4 FOR 1)
WHEN ‘0’ THEN 0
WHEN ‘1’ THEN 1
WHEN ‘2’ THEN 2
WHEN ‘3’ THEN 3
WHEN ‘4’ THEN 4
WHEN ‘5’ THEN 5
WHEN ‘6’ THEN 6
WHEN ‘7’ THEN 7
WHEN ‘8’ THEN 8
WHEN ‘9’ THEN 9
WHEN ‘A’ THEN 10
WHEN ‘B’ THEN 11
WHEN ‘C’ THEN 12
WHEN ‘D’ THEN 13
WHEN ‘E’ THEN 14
WHEN ‘F’ THEN 15
END

Roland Wenzlofsky
 

Roland Wenzlofsky is a graduated computer scientist and Data Warehouse professional working with the Teradata database system for more than 15 years. He is experienced in the fields of banking and telecommunication with a strong focus on performance optimization.

  • Avatar Beat Brüngger says:

    Hi, if you are on Teradata >= 14.00 you can try:
    SELECT ASCII(‘A’);
    ->> Returns the decimal representation of the first character in string_expr as a NUMBER value.

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