diff options
Diffstat (limited to 'sql/sql_select.cc')
| -rw-r--r-- | sql/sql_select.cc | 22 |
1 files changed, 16 insertions, 6 deletions
diff --git a/sql/sql_select.cc b/sql/sql_select.cc index 9456211a7cc..330df610b46 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -2119,10 +2119,17 @@ get_best_combination(JOIN *join) j->type=JT_REF; /* Must read with repeat */ else if (ref_key == j->ref.key_copy) { /* Should never be reached */ - j->type=JT_CONST; /* purecov: deadcode */ + /* + This happen if we are using a constant expression in the ON part + of an LEFT JOIN. + SELECT * FROM a LEFT JOIN b ON b.key=30 + Here we should not mark the table as a 'const' as a field may + have a 'normal' value or a NULL value. + */ + j->type=JT_CONST; if (join->const_tables == tablenr) { - join->const_tables++; /* purecov: deadcode */ + join->const_tables++; join->const_table_map|=form->map; } } @@ -2251,7 +2258,7 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond) used_tables|=current_map; if (tab->type == JT_REF && tab->quick && - tab->ref.key == tab->quick->index && + (uint) tab->ref.key == tab->quick->index && tab->ref.key_length < tab->quick->max_used_key_length) { /* Range uses longer key; Use this instead of ref on key */ @@ -2689,8 +2696,8 @@ static void update_depend_map(JOIN *join, ORDER *order) /* -** simple_order is set to 1 if sort_order only uses fields from head table -** and the head table is not a LEFT JOIN table + simple_order is set to 1 if sort_order only uses fields from head table + and the head table is not a LEFT JOIN table */ static ORDER * @@ -4331,8 +4338,11 @@ join_read_const(JOIN_TAB *tab) } store_record(table,1); } - else if (!table->status) // Only happens with left join + else if (!(table->status & ~STATUS_NULL_ROW)) // Only happens with left join + { + table->status=0; restore_record(table,1); // restore old record + } table->null_row=0; return table->status ? -1 : 0; } |