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SQL Anywhere 11.0.1 » SQL Anywhere Server - SQL Reference » Using SQL » SQL functions » SQL functions (E-O)

 

ISNUMERIC function [Miscellaneous]

Determines if a string argument is a valid number.

Syntax
ISNUMERIC( string )
Parameters
  • string   The string to be analyzed to determine if the string represents a valid number.

Returns

INT

Remarks

ISNUMERIC returns 1 when the input string evaluates to a valid integer or floating point number; otherwise it returns 0. The function also returns 0 if the string contains only blanks or is NULL.

Following are values that also cause the ISNUMERIC function to return 0:

  • Values that use the letter d or D as the exponent separator. For example, 1d2.

  • Special values such as NAN, 0x12, INF, and INFINITY.

  • NULL (for example, SELECT ISNUMERIC( NULL );)

Standards and compatibility
  • SQL/2003   Vendor extension.

Example

The following example imports data from an external file, exports rows that contain invalid values, and copies the remaining rows to a permanent table. In this example, the ISNUMERIC statement validates that the values in height_in_cms values are numeric.

CREATE GLOBAL TEMPORARY TABLE MyData(
      person VARCHAR(100),
      birth_date VARCHAR(30),
      height_in_cms VARCHAR(10)
   ) ON COMMIT PRESERVE ROWS;
   LOAD TABLE MyData FROM 'exported.dat';
   UNLOAD
      SELECT *
      FROM MyData
      WHERE ISDATE( birth_date ) = 0
  OR ISNUMERIC( height_in_cms ) = 0
   TO 'badrows.dat';
   INSERT INTO PermData
      SELECT person, birth_date, height_in_cms
      FROM MyData
      WHERE ISDATE( birth_date ) = 1
  AND ISNUMERIC( height_in_cms ) = 1;
   COMMIT;
   DROP TABLE MyData;