diff options
| -rw-r--r-- | mysql-test/r/type_newdecimal.result | 20 | ||||
| -rw-r--r-- | mysql-test/t/type_newdecimal.test | 21 | ||||
| -rw-r--r-- | sql/sql_select.cc | 38 |
3 files changed, 76 insertions, 3 deletions
diff --git a/mysql-test/r/type_newdecimal.result b/mysql-test/r/type_newdecimal.result index 75d9582a23c..b53b49bd0dd 100644 --- a/mysql-test/r/type_newdecimal.result +++ b/mysql-test/r/type_newdecimal.result @@ -1499,4 +1499,24 @@ SELECT 1 FROM t1 GROUP BY @b := @a, @b; 1 1 DROP TABLE t1; +CREATE TABLE t1 SELECT 0.123456789012345678901234567890123456 AS f1; +Warnings: +Note 1265 Data truncated for column 'f1' at row 1 +DESC t1; +Field Type Null Key Default Extra +f1 decimal(31,30) NO 0.000000000000000000000000000000 +SELECT f1 FROM t1; +f1 +0.123456789012345678901234567890 +DROP TABLE t1; +CREATE TABLE t1 SELECT 123451234512345123451234512345123451234512345.678906789067890678906789067890678906789067890 AS f1; +Warnings: +Warning 1264 Out of range value adjusted for column 'f1' at row 1 +DESC t1; +Field Type Null Key Default Extra +f1 decimal(59,30) NO 0.000000000000000000000000000000 +SELECT f1 FROM t1; +f1 +99999999999999999999999999999.999999999999999999999999999999 +DROP TABLE t1; End of 5.0 tests diff --git a/mysql-test/t/type_newdecimal.test b/mysql-test/t/type_newdecimal.test index 5a631b6163e..cb7e0c4163a 100644 --- a/mysql-test/t/type_newdecimal.test +++ b/mysql-test/t/type_newdecimal.test @@ -1195,6 +1195,25 @@ SELECT 1 FROM t1 GROUP BY @b := @a, @b; DROP TABLE t1; ---echo End of 5.0 tests +# +# Bug #24907: unpredictable (display) precission, if input precission +# increases +# +# As per 10.1.1. Overview of Numeric Types, type (new) DECIMAL has a +# maxmimum precision of 30 places after the decimal point. Show that +# temp field creation beyond that works and throws a truncation warning. +# DECIMAL(37,36) should be adjusted to DECIMAL(31,30). +CREATE TABLE t1 SELECT 0.123456789012345678901234567890123456 AS f1; +DESC t1; +SELECT f1 FROM t1; +DROP TABLE t1; +# too many decimal places, AND too many digits altogether (90 = 45+45). +# should preserve integers (65 = 45+20) +CREATE TABLE t1 SELECT 123451234512345123451234512345123451234512345.678906789067890678906789067890678906789067890 AS f1; +DESC t1; +SELECT f1 FROM t1; +DROP TABLE t1; + +--echo End of 5.0 tests diff --git a/sql/sql_select.cc b/sql/sql_select.cc index 1d11f23d854..8227d09fe85 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -8960,9 +8960,43 @@ static Field *create_tmp_field_from_item(THD *thd, Item *item, TABLE *table, new_field->set_derivation(item->collation.derivation); break; case DECIMAL_RESULT: - new_field= new Field_new_decimal(item->max_length, maybe_null, item->name, - table, item->decimals, item->unsigned_flag); + { + uint8 dec= item->decimals; + uint8 intg= ((Item_decimal *) item)->decimal_precision() - dec; + uint8 len= item->max_length; + + /* + Trying to put too many digits overall in a DECIMAL(prec,dec) + will always throw a warning. We must limit dec to + DECIMAL_MAX_SCALE however to prevent an assert() later. + */ + + if (dec > 0) + { + signed int overflow; + + dec= min(dec, DECIMAL_MAX_SCALE); + + /* + If the value still overflows the field with the corrected dec, + we'll throw out decimals rather than integers. This is still + bad and of course throws a truncation warning. + +1: for decimal point + */ + + overflow= my_decimal_precision_to_length(intg + dec, dec, + item->unsigned_flag) - len; + + if (overflow > 0) + dec= max(0, dec - overflow); // too long, discard fract + else + len -= item->decimals - dec; // corrected value fits + } + + new_field= new Field_new_decimal(len, maybe_null, item->name, + table, dec, item->unsigned_flag); break; + } case ROW_RESULT: default: // This case should never be choosen |