ORA-32766: instr with negative offset: use varchar semantics on LOBs

michaeljet

Cause: The current varchar behavioris 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, whichpoints to 'c' and moving

backward, i.e. 'd' is ignored. This is symmetric toinstr('dcba','dc',2,1), which

returns 0.

Action: ORACLE uses the same varcharsemantics on LOBs (instr). Using the

same example, instr(to_clob('abcd'), 'cd', -2, 1) willreturn 3 as in the varchar case.