From 3507a52e60a20b01dd1d200f5a4f8b601cb0f55b Mon Sep 17 00:00:00 2001 From: unknown Date: Sun, 21 Nov 2004 12:04:27 +0300 Subject: A fix and test case for Bug#6297 "prepared statement, wrong handling of IS NULL": we must not only set Item::null_value in Item_param, but implement Item_param::is_null() to work well with IS NULL/IS NOT NULL clauses. mysql-test/r/ps.result: Test case for Bug#6297: test results fixed. mysql-test/t/ps.test: A test case for Bug#6297 "prepared statement, wrong handling of IS NULL" sql/item.h: A fix for Bug#6297: we must not only set null_value in Item_param, but also implement Item_param::is_null() to work well with IS NULL/ IS NOT NULL. Item::is_null() commented. --- sql/item.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'sql') diff --git a/sql/item.h b/sql/item.h index 547577a7ee0..ccb0fda1c49 100644 --- a/sql/item.h +++ b/sql/item.h @@ -266,6 +266,14 @@ public: virtual bool get_time(TIME *ltime); virtual bool get_date_result(TIME *ltime,uint fuzzydate) { return get_date(ltime,fuzzydate); } + /* + This function is used only in Item_func_isnull/Item_func_isnotnull + (implementations of IS NULL/IS NOT NULL clauses). Item_func_is{not}null + calls this method instead of one of val/result*() methods, which + normally will set null_value. This allows to determine nullness of + a complex expression without fully evaluating it. + Any new item which can be NULL must implement this call. + */ virtual bool is_null() { return 0; } /* it is "top level" item of WHERE clause and we do not need correct NULL @@ -573,6 +581,8 @@ public: void print(String *str) { str->append('?'); } /* parameter never equal to other parameter of other item */ bool eq(const Item *item, bool binary_cmp) const { return 0; } + bool is_null() + { DBUG_ASSERT(state != NO_VALUE); return state == NULL_VALUE; } }; class Item_int :public Item_num -- cgit v1.2.1