Oracle : Ошибка ORA-32766

"instr with negative offset: use varchar semantics on LOBs"
*Cause: The current varchar behavior is different.
e.g. instr('abcd', 'cd', -2, 1) returns 3, whereas
instr(to_clob('abcd'), 'cd', -2, 1) returns 0, (i.e. no match),
because the reverse search starts from offset -2, which points
to 'c' and moving backward, i.e. 'd' is ignored.
This is symmetric to instr('dcba','dc',2,1), which returns 0.
*Action: ORACLE uses the same varchar semantics on LOBs (instr).
Using the same example, instr(to_clob('abcd'), 'cd', -2, 1)
will return 3 as in the varchar case.

Попробовать перевести

Поискать эту ошибку на форуме