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fixed substring() length calculation in case of constant negative argument (BUG#10269)

mysql-test/r/func_str.result:
  Correct length reporting from substring()
mysql-test/t/func_str.test:
  Correct length reporting from substring()
sql/item_strfunc.cc:
  fixed substring() length calculation in case of constant negative argument
This commit is contained in:
unknown
2005-06-28 21:45:11 +03:00
parent dadf91f0ff
commit 2637338014
3 changed files with 26 additions and 1 deletions

View File

@ -800,3 +800,18 @@ SELECT * FROM t1, t2 WHERE num=substring(str from 1 for 6);
str num str num
notnumber 0 notnumber 0
DROP TABLE t1,t2; DROP TABLE t1,t2;
create table t1 (b varchar(5));
insert t1 values ('ab'), ('abc'), ('abcd'), ('abcde');
select *,substring(b,1),substring(b,-1),substring(b,-2),substring(b,-3),substring(b,-4),substring(b,-5) from t1;
b substring(b,1) substring(b,-1) substring(b,-2) substring(b,-3) substring(b,-4) substring(b,-5)
ab ab b ab
abc abc c bc abc
abcd abcd d cd bcd abcd
abcde abcde e de cde bcde abcde
select * from (select *,substring(b,1),substring(b,-1),substring(b,-2),substring(b,-3),substring(b,-4),substring(b,-5) from t1) t;
b substring(b,1) substring(b,-1) substring(b,-2) substring(b,-3) substring(b,-4) substring(b,-5)
ab ab b ab
abc abc c bc abc
abcd abcd d cd bcd abcd
abcde abcde e de cde bcde abcde
drop table t1;

View File

@ -541,3 +541,12 @@ SELECT * FROM t1, t2 WHERE num=str;
SELECT * FROM t1, t2 WHERE num=substring(str from 1 for 6); SELECT * FROM t1, t2 WHERE num=substring(str from 1 for 6);
DROP TABLE t1,t2; DROP TABLE t1,t2;
#
# Correct length reporting from substring() (BUG#10269)
#
create table t1 (b varchar(5));
insert t1 values ('ab'), ('abc'), ('abcd'), ('abcde');
select *,substring(b,1),substring(b,-1),substring(b,-2),substring(b,-3),substring(b,-4),substring(b,-5) from t1;
select * from (select *,substring(b,1),substring(b,-1),substring(b,-2),substring(b,-3),substring(b,-4),substring(b,-5) from t1) t;
drop table t1;

View File

@ -1065,7 +1065,8 @@ void Item_func_substr::fix_length_and_dec()
collation.set(args[0]->collation); collation.set(args[0]->collation);
if (args[1]->const_item()) if (args[1]->const_item())
{ {
int32 start=(int32) args[1]->val_int()-1; int32 start= (int32) args[1]->val_int();
start= (int32)((start < 0) ? max_length + start : start - 1);
if (start < 0 || start >= (int32) max_length) if (start < 0 || start >= (int32) max_length)
max_length=0; /* purecov: inspected */ max_length=0; /* purecov: inspected */
else else