diff options
Diffstat (limited to 'sql/item_cmpfunc.cc')
| -rw-r--r-- | sql/item_cmpfunc.cc | 36 |
1 files changed, 32 insertions, 4 deletions
diff --git a/sql/item_cmpfunc.cc b/sql/item_cmpfunc.cc index ce3096da778..be44d490415 100644 --- a/sql/item_cmpfunc.cc +++ b/sql/item_cmpfunc.cc @@ -680,17 +680,45 @@ int Arg_comparator::compare_e_int_diff_signedness() int Arg_comparator::compare_row() { int res= 0; + bool was_null= 0; (*a)->bring_value(); (*b)->bring_value(); uint n= (*a)->cols(); for (uint i= 0; i<n; i++) { - if ((res= comparators[i].compare())) - return res; + res= comparators[i].compare(); if (owner->null_value) - return -1; + { + // NULL was compared + switch (owner->functype()) { + case Item_func::NE_FUNC: + break; // NE never aborts on NULL even if abort_on_null is set + case Item_func::LT_FUNC: + case Item_func::LE_FUNC: + case Item_func::GT_FUNC: + case Item_func::GE_FUNC: + return -1; // <, <=, > and >= always fail on NULL + default: // EQ_FUNC + if (owner->abort_on_null) + return -1; // We do not need correct NULL returning + } + was_null= 1; + owner->null_value= 0; + res= 0; // continue comparison (maybe we will meet explicit difference) + } + else if (res) + return res; } - return res; + if (was_null) + { + /* + There was NULL(s) in comparison in some parts, but there was no + explicit difference in other parts, so we have to return NULL. + */ + owner->null_value= 1; + return -1; + } + return 0; } int Arg_comparator::compare_e_row() |