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Commit c51d7acf authored by bar@mysql.com's avatar bar@mysql.com
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1. When mixing NULL to a character string, 

the result takes its charset/collation
attributes from the character string,
e.g.  SELECT func(NULL, _latin2'string')
now returns a latin2 result. This is
done by introducing a new derivation
(aka coercibility) level DERIVATION_IGNORABLE,
which is used with Item_null.
2. 'Pure' NULL is now BINARY(0), not CHAR(0).
I.e. NULL is now more typeless.
parent 2f500447
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Inline Side-by-side
Showing with 181 additions and 17 deletions
mysql-test/r/metadata.result
View file @ c51d7acf
......@@ -5,7 +5,7 @@ def 1 8 1 1 N 32769 0 8
def 1.0 5 3 3 N 32769 1 8
def -1 8 1 2 N 32769 0 8
def hello 254 5 5 N 1 31 8
def NULL 6 0 0 Y 32768 0 8
def NULL 6 0 0 Y 32896 0 63
1 1.0 -1 hello NULL
1 1.0 -1 hello NULL
create table t1 (a tinyint, b smallint, c mediumint, d int, e bigint, f float(3,2), g double(4,3), h decimal(5,4), i year, j date, k timestamp, l datetime, m enum('a','b'), n set('a','b'), o char(10));
......
mysql-test/r/null.result
View file @ c51d7acf
......@@ -175,3 +175,97 @@ explain select * from t1 where i=2 or i is null;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ref i i 4 const 7 Using where; Using index
drop table t1;
set names latin2;
create table t1 select
null as c00,
if(1, null, 'string') as c01,
if(0, null, 'string') as c02,
ifnull(null, 'string') as c03,
ifnull('string', null) as c04,
case when 0 then null else 'string' end as c05,
case when 1 then null else 'string' end as c06,
coalesce(null, 'string') as c07,
coalesce('string', null) as c08,
least('string',null) as c09,
least(null, 'string') as c10,
greatest('string',null) as c11,
greatest(null, 'string') as c12,
nullif('string', null) as c13,
nullif(null, 'string') as c14,
trim('string' from null) as c15,
trim(null from 'string') as c16,
substring_index('string', null, 1) as c17,
substring_index(null, 'string', 1) as c18,
elt(1, null, 'string') as c19,
elt(1, 'string', null) as c20,
concat('string', null) as c21,
concat(null, 'string') as c22,
concat_ws('sep', 'string', null) as c23,
concat_ws('sep', null, 'string') as c24,
concat_ws(null, 'string', 'string') as c25,
make_set(3, 'string', null) as c26,
make_set(3, null, 'string') as c27,
export_set(3, null, 'off', 'sep') as c29,
export_set(3, 'on', null, 'sep') as c30,
export_set(3, 'on', 'off', null) as c31,
replace(null, 'from', 'to') as c32,
replace('str', null, 'to') as c33,
replace('str', 'from', null) as c34,
insert('str', 1, 2, null) as c35,
insert(null, 1, 2, 'str') as c36,
lpad('str', 10, null) as c37,
rpad(null, 10, 'str') as c38;
show create table t1;
Table Create Table
t1 CREATE TABLE `t1` (
`c00` binary(0) default NULL,
`c01` varchar(6) character set latin2 default NULL,
`c02` varchar(6) character set latin2 default NULL,
`c03` varchar(6) character set latin2 NOT NULL default '',
`c04` varchar(6) character set latin2 default NULL,
`c05` varchar(6) character set latin2 default NULL,
`c06` varchar(6) character set latin2 default NULL,
`c07` varchar(6) character set latin2 default NULL,
`c08` varchar(6) character set latin2 default NULL,
`c09` varchar(6) character set latin2 NOT NULL default '',
`c10` varchar(6) character set latin2 NOT NULL default '',
`c11` varchar(6) character set latin2 NOT NULL default '',
`c12` varchar(6) character set latin2 NOT NULL default '',
`c13` varchar(6) character set latin2 default NULL,
`c14` char(0) character set latin2 default NULL,
`c15` char(0) character set latin2 default NULL,
`c16` varchar(6) character set latin2 default NULL,
`c17` varchar(6) character set latin2 default NULL,
`c18` char(0) character set latin2 default NULL,
`c19` varchar(6) character set latin2 default NULL,
`c20` varchar(6) character set latin2 default NULL,
`c21` varchar(6) character set latin2 default NULL,
`c22` varchar(6) character set latin2 default NULL,
`c23` varchar(9) character set latin2 default NULL,
`c24` varchar(9) character set latin2 default NULL,
`c25` varchar(12) character set latin2 default NULL,
`c26` varchar(7) character set latin2 default NULL,
`c27` varchar(7) character set latin2 default NULL,
`c29` longtext character set latin2,
`c30` longtext character set latin2,
`c31` varchar(192) character set latin2 default NULL,
`c32` char(0) character set latin2 default NULL,
`c33` char(3) character set latin2 default NULL,
`c34` char(3) character set latin2 default NULL,
`c35` char(3) character set latin2 default NULL,
`c36` char(3) character set latin2 default NULL,
`c37` varchar(10) character set latin2 default NULL,
`c38` varchar(10) character set latin2 default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
select
case 'str' when 'STR' then 'str' when null then 'null' end as c01,
case 'str' when null then 'null' when 'STR' then 'str' end as c02,
field(null, 'str1', 'str2') as c03,
field('str1','STR1', null) as c04,
field('str1', null, 'STR1') as c05,
'string' in ('STRING', null) as c08,
'string' in (null, 'STRING') as c09;
c01 c02 c03 c04 c05 c08 c09
str str 0 1 2 1 1
set names latin1;
mysql-test/r/ps_2myisam.result
View file @ c51d7acf
......@@ -1790,7 +1790,7 @@ t5 CREATE TABLE `t5` (
`param10` bigint(20) default NULL,
`const11` int(4) default NULL,
`param11` bigint(20) default NULL,
`const12` char(0) default NULL,
`const12` binary(0) default NULL,
`param12` bigint(20) default NULL,
`param13` double default NULL,
`param14` longtext,
......@@ -1820,7 +1820,7 @@ def test t5 t5 const10 const10 3 10 9 N 32769 0 63
def test t5 t5 param10 param10 8 20 9 Y 32768 0 63
def test t5 t5 const11 const11 3 4 4 Y 32768 0 63
def test t5 t5 param11 param11 8 20 4 Y 32768 0 63
def test t5 t5 const12 const12 254 0 0 Y 0 0 8
def test t5 t5 const12 const12 254 0 0 Y 128 0 63
def test t5 t5 param12 param12 8 20 0 Y 32768 0 63
def test t5 t5 param13 param13 5 20 0 Y 32768 31 63
def test t5 t5 param14 param14 252 16777215 0 Y 16 0 8
......
mysql-test/r/ps_3innodb.result
View file @ c51d7acf
......@@ -1773,7 +1773,7 @@ t5 CREATE TABLE `t5` (
`param10` bigint(20) default NULL,
`const11` int(4) default NULL,
`param11` bigint(20) default NULL,
`const12` char(0) default NULL,
`const12` binary(0) default NULL,
`param12` bigint(20) default NULL,
`param13` double default NULL,
`param14` longtext,
......@@ -1803,7 +1803,7 @@ def test t5 t5 const10 const10 3 10 9 N 32769 0 63
def test t5 t5 param10 param10 8 20 9 Y 32768 0 63
def test t5 t5 const11 const11 3 4 4 Y 32768 0 63
def test t5 t5 param11 param11 8 20 4 Y 32768 0 63
def test t5 t5 const12 const12 254 0 0 Y 0 0 8
def test t5 t5 const12 const12 254 0 0 Y 128 0 63
def test t5 t5 param12 param12 8 20 0 Y 32768 0 63
def test t5 t5 param13 param13 5 20 0 Y 32768 31 63
def test t5 t5 param14 param14 252 16777215 0 Y 16 0 8
......
mysql-test/r/ps_4heap.result
View file @ c51d7acf
......@@ -1774,7 +1774,7 @@ t5 CREATE TABLE `t5` (
`param10` bigint(20) default NULL,
`const11` int(4) default NULL,
`param11` bigint(20) default NULL,
`const12` char(0) default NULL,
`const12` binary(0) default NULL,
`param12` bigint(20) default NULL,
`param13` double default NULL,
`param14` longtext,
......@@ -1804,7 +1804,7 @@ def test t5 t5 const10 const10 3 10 9 N 32769 0 63
def test t5 t5 param10 param10 8 20 9 Y 32768 0 63
def test t5 t5 const11 const11 3 4 4 Y 32768 0 63
def test t5 t5 param11 param11 8 20 4 Y 32768 0 63
def test t5 t5 const12 const12 254 0 0 Y 0 0 8
def test t5 t5 const12 const12 254 0 0 Y 128 0 63
def test t5 t5 param12 param12 8 20 0 Y 32768 0 63
def test t5 t5 param13 param13 5 20 0 Y 32768 31 63
def test t5 t5 param14 param14 252 16777215 0 Y 16 0 8
......
mysql-test/r/ps_5merge.result
View file @ c51d7acf
......@@ -1713,7 +1713,7 @@ t5 CREATE TABLE `t5` (
`param10` bigint(20) default NULL,
`const11` int(4) default NULL,
`param11` bigint(20) default NULL,
`const12` char(0) default NULL,
`const12` binary(0) default NULL,
`param12` bigint(20) default NULL,
`param13` double default NULL,
`param14` longtext,
......@@ -1743,7 +1743,7 @@ def test t5 t5 const10 const10 3 10 9 N 32769 0 63
def test t5 t5 param10 param10 8 20 9 Y 32768 0 63
def test t5 t5 const11 const11 3 4 4 Y 32768 0 63
def test t5 t5 param11 param11 8 20 4 Y 32768 0 63
def test t5 t5 const12 const12 254 0 0 Y 0 0 8
def test t5 t5 const12 const12 254 0 0 Y 128 0 63
def test t5 t5 param12 param12 8 20 0 Y 32768 0 63
def test t5 t5 param13 param13 5 20 0 Y 32768 31 63
def test t5 t5 param14 param14 252 16777215 0 Y 16 0 8
......@@ -4723,7 +4723,7 @@ t5 CREATE TABLE `t5` (
`param10` bigint(20) default NULL,
`const11` int(4) default NULL,
`param11` bigint(20) default NULL,
`const12` char(0) default NULL,
`const12` binary(0) default NULL,
`param12` bigint(20) default NULL,
`param13` double default NULL,
`param14` longtext,
......@@ -4753,7 +4753,7 @@ def test t5 t5 const10 const10 3 10 9 N 32769 0 63
def test t5 t5 param10 param10 8 20 9 Y 32768 0 63
def test t5 t5 const11 const11 3 4 4 Y 32768 0 63
def test t5 t5 param11 param11 8 20 4 Y 32768 0 63
def test t5 t5 const12 const12 254 0 0 Y 0 0 8
def test t5 t5 const12 const12 254 0 0 Y 128 0 63
def test t5 t5 param12 param12 8 20 0 Y 32768 0 63
def test t5 t5 param13 param13 5 20 0 Y 32768 31 63
def test t5 t5 param14 param14 252 16777215 0 Y 16 0 8
......
mysql-test/r/ps_6bdb.result
View file @ c51d7acf
......@@ -1773,7 +1773,7 @@ t5 CREATE TABLE `t5` (
`param10` bigint(20) default NULL,
`const11` int(4) default NULL,
`param11` bigint(20) default NULL,
`const12` char(0) default NULL,
`const12` binary(0) default NULL,
`param12` bigint(20) default NULL,
`param13` double default NULL,
`param14` longtext,
......@@ -1803,7 +1803,7 @@ def test t5 t5 const10 const10 3 10 9 N 32769 0 63
def test t5 t5 param10 param10 8 20 9 Y 32768 0 63
def test t5 t5 const11 const11 3 4 4 Y 32768 0 63
def test t5 t5 param11 param11 8 20 4 Y 32768 0 63
def test t5 t5 const12 const12 254 0 0 Y 0 0 8
def test t5 t5 const12 const12 254 0 0 Y 128 0 63
def test t5 t5 param12 param12 8 20 0 Y 32768 0 63
def test t5 t5 param13 param13 5 20 0 Y 32768 31 63
def test t5 t5 param14 param14 252 16777215 0 Y 16 0 8
......
mysql-test/r/ps_7ndb.result
View file @ c51d7acf
......@@ -1749,7 +1749,7 @@ t5 CREATE TABLE `t5` (
`param10` bigint(20) default NULL,
`const11` int(4) default NULL,
`param11` bigint(20) default NULL,
`const12` char(0) default NULL,
`const12` binary(0) default NULL,
`param12` bigint(20) default NULL,
`param13` double default NULL,
`param14` longtext,
......@@ -1779,7 +1779,7 @@ def test t5 t5 const10 const10 3 10 9 N 32769 0 63
def test t5 t5 param10 param10 8 20 9 Y 32768 0 63
def test t5 t5 const11 const11 3 4 4 Y 32768 0 63
def test t5 t5 param11 param11 8 20 4 Y 32768 0 63
def test t5 t5 const12 const12 254 0 0 Y 0 0 8
def test t5 t5 const12 const12 254 0 0 Y 128 0 63
def test t5 t5 param12 param12 8 20 0 Y 32768 0 63
def test t5 t5 param13 param13 5 20 0 Y 32768 31 63
def test t5 t5 param14 param14 252 16777215 0 Y 16 0 8
......
mysql-test/t/null.test
View file @ c51d7acf
......@@ -119,3 +119,70 @@ alter table t1 change i i int not null;
explain select * from t1 where i=2 or i is null;
drop table t1;
#
# NULL has its own type BINARY(0) by default.
# But NULL should be weaker than a constant
# when mixing charsets/collations
#
set names latin2;
# Check that result type is taken from a non-null string
create table t1 select
null as c00,
if(1, null, 'string') as c01,
if(0, null, 'string') as c02,
ifnull(null, 'string') as c03,
ifnull('string', null) as c04,
case when 0 then null else 'string' end as c05,
case when 1 then null else 'string' end as c06,
coalesce(null, 'string') as c07,
coalesce('string', null) as c08,
least('string',null) as c09,
least(null, 'string') as c10,
greatest('string',null) as c11,
greatest(null, 'string') as c12,
nullif('string', null) as c13,
nullif(null, 'string') as c14,
trim('string' from null) as c15,
trim(null from 'string') as c16,
substring_index('string', null, 1) as c17,
substring_index(null, 'string', 1) as c18,
elt(1, null, 'string') as c19,
elt(1, 'string', null) as c20,
concat('string', null) as c21,
concat(null, 'string') as c22,
concat_ws('sep', 'string', null) as c23,
concat_ws('sep', null, 'string') as c24,
concat_ws(null, 'string', 'string') as c25,
make_set(3, 'string', null) as c26,
make_set(3, null, 'string') as c27,
export_set(3, null, 'off', 'sep') as c29,
export_set(3, 'on', null, 'sep') as c30,
export_set(3, 'on', 'off', null) as c31,
replace(null, 'from', 'to') as c32,
replace('str', null, 'to') as c33,
replace('str', 'from', null) as c34,
insert('str', 1, 2, null) as c35,
insert(null, 1, 2, 'str') as c36,
lpad('str', 10, null) as c37,
rpad(null, 10, 'str') as c38;
show create table t1;
drop table t1;
#
# Check that comparison is done according to
# non-null string collation, i.e. case insensitively,
# rather than according to NULL's collation, i.e. case sensitively
#
-- in field
select
case 'str' when 'STR' then 'str' when null then 'null' end as c01,
case 'str' when null then 'null' when 'STR' then 'str' end as c02,
field(null, 'str1', 'str2') as c03,
field('str1','STR1', null) as c04,
field('str1', null, 'STR1') as c05,
'string' in ('STRING', null) as c08,
'string' in (null, 'STRING') as c09;
# Restore charset to the default value.
set names latin1;
sql/item.cc
View file @ c51d7acf
......@@ -376,13 +376,13 @@ bool DTCollation::aggregate(DTCollation &dt, uint flags)
}
else if ((flags & MY_COLL_ALLOW_COERCIBLE_CONV) &&
derivation < dt.derivation &&
dt.derivation == DERIVATION_COERCIBLE)
dt.derivation >= DERIVATION_COERCIBLE)
{
// Do nothing;
}
else if ((flags & MY_COLL_ALLOW_COERCIBLE_CONV) &&
dt.derivation < derivation &&
derivation == DERIVATION_COERCIBLE)
derivation >= DERIVATION_COERCIBLE)
{
set(dt);
strong= nagg;
......
sql/item.h
View file @ c51d7acf
......@@ -31,6 +31,7 @@ void item_init(void); /* Init item functions */
enum Derivation
{
DERIVATION_IGNORABLE= 4,
DERIVATION_COERCIBLE= 3,
DERIVATION_IMPLICIT= 2,
DERIVATION_NONE= 1,
......@@ -98,6 +99,7 @@ class DTCollation {
{
switch(derivation)
{
case DERIVATION_IGNORABLE: return "IGNORABLE";
case DERIVATION_COERCIBLE: return "COERCIBLE";
case DERIVATION_IMPLICIT: return "IMPLICIT";
case DERIVATION_EXPLICIT: return "EXPLICIT";
......@@ -440,6 +442,7 @@ class Item_null :public Item
max_length= 0;
name= name_par ? name_par : (char*) "NULL";
fixed= 1;
collation.set(&my_charset_bin, DERIVATION_IGNORABLE);
}
enum Type type() const { return NULL_ITEM; }
bool eq(const Item *item, bool binary_cmp) const;
......
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