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F_PRED

function from adhoc

Entrypoint predecessor not compatible with UTF-8 - use U_PRED

U_PRED

function from adhoc

Entrypoint u_predecessor compatible with UTF-8

Inputs/Outputs

   Input       CSTRING(1)     Character
               INTEGER        Amount of characters before the character in ASCII-Table
   Output      CSTRING(1)     n-predecessor of character from parameter 1

Syntax

   Is parameter 2 equal to 512 (or multiple of 512) the return is the same as the input.
   Test SQL
   SELECT 'b' AS ISCORRECT, F_PRED('a', -1) FROM RDB$DATABASE;
   SELECT 'a' AS ISCORRECT, F_PRED('b', 1) FROM RDB$DATABASE;
   SELECT 'a' AS ISCORRECT, F_PRED('a', 512) FROM RDB$DATABASE;
   SELECT NULL AS ISCORRECT, F_PRED(NULL, NULL) FROM RDB$DATABASE;
   SELECT '¢' AS ISCORRECT, U_PRED('£', 1) FROM RDB$DATABASE;
   SELECT '¡' AS ISCORRECT, U_PRED('£', 2) FROM RDB$DATABASE;
   SELECT 'あ' AS ISCORRECT, U_PRED('え', 6) FROM RDB$DATABASE;
   SELECT NULL AS ISCORRECT, U_PRED(NULL, NULL) FROM RDB$DATABASE;