diff options
Diffstat (limited to 'sql/item.cc')
| -rw-r--r-- | sql/item.cc | 50 |
1 files changed, 48 insertions, 2 deletions
diff --git a/sql/item.cc b/sql/item.cc index 682f88317f1..7b657aeadc6 100644 --- a/sql/item.cc +++ b/sql/item.cc @@ -544,7 +544,14 @@ uint Item::decimal_precision() const unsigned_flag); return MY_MIN(prec, DECIMAL_MAX_PRECISION); } - return MY_MIN(max_char_length(), DECIMAL_MAX_PRECISION); + uint res= max_char_length(); + /* + Return at least one decimal digit, even if Item::max_char_length() + returned 0. This is important to avoid attempts to create fields of types + INT(0) or DECIMAL(0,0) when converting NULL or empty strings to INT/DECIMAL: + CREATE TABLE t1 AS SELECT CONVERT(NULL,SIGNED) AS a; + */ + return res ? MY_MIN(res, DECIMAL_MAX_PRECISION) : 1; } @@ -1182,7 +1189,8 @@ Item *Item_cache::safe_charset_converter(THD *thd, CHARSET_INFO *tocs) if (conv == example) return this; Item_cache *cache; - if (!conv || !(cache= new (thd->mem_root) Item_cache_str(thd, conv))) + if (!conv || conv->fix_fields(thd, (Item **) NULL) || + !(cache= new (thd->mem_root) Item_cache_str(thd, conv))) return NULL; // Safe conversion is not possible, or OEM cache->setup(thd, conv); cache->fixed= false; // Make Item::fix_fields() happy @@ -2878,6 +2886,44 @@ void Item_field::fix_after_pullout(st_select_lex *new_parent, Item **ref) depended_from= NULL; if (context) { + bool need_change= false; + /* + Suppose there are nested selects: + + select_id=1 + select_id=2 + select_id=3 <----+ + select_id=4 -+ + select_id=5 --+ + + Suppose, pullout operation has moved anything that had select_id=4 or 5 + in to select_id=3. + + If this Item_field had a name resolution context pointing into select_lex + with id=4 or id=5, it needs a new name resolution context. + + However, it could also be that this object is a part of outer reference: + Item_ref(Item_field(field in select with select_id=1))). + - The Item_ref object has a context with select_id=5, and so needs a new + name resolution context. + - The Item_field object has a context with select_id=1, and doesn't need + a new name resolution context. + + So, the following loop walks from Item_field's current context upwards. + If we find that the select we've been pulled out to is up there, we + create the new name resolution context. Otherwise, we don't. + */ + for (Name_resolution_context *ct= context; ct; ct= ct->outer_context) + { + if (new_parent == ct->select_lex) + { + need_change= true; + break; + } + } + if (!need_change) + return; + Name_resolution_context *ctx= new Name_resolution_context(); if (context->select_lex == new_parent) { |