From a21cd97c3506a70297afc3dd3f64cdfd2dc0a4e6 Mon Sep 17 00:00:00 2001 From: Georgi Kodinov Date: Fri, 20 Nov 2009 12:10:47 +0200 Subject: Bug #45261 : Crash, stored procedure + decimal Bug #48370 Absolutely wrong calculations with GROUP BY and decimal fields when using IF Added the test cases in the above two bugs for regression testing. Added additional tests that demonstrate a incomplete fix. Added a new factory method for Field_new_decimal to create a field from an (decimal returning) Item. In the new method made sure that all the precision and length variables are capped in a proper way. This is required because Item's can have larger precision than the decimal fields and thus need to be capped when creating a field based on an Item type. Fixed the wrong typecast to Item_decimal. --- sql/field.cc | 44 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) (limited to 'sql/field.cc') diff --git a/sql/field.cc b/sql/field.cc index 354c911e1c0..01ccc338782 100644 --- a/sql/field.cc +++ b/sql/field.cc @@ -2486,6 +2486,50 @@ Field_new_decimal::Field_new_decimal(uint32 len_arg, } +Field *Field_new_decimal::create_from_item (Item *item) +{ + uint8 dec= item->decimals; + uint8 intg= item->decimal_precision() - dec; + uint32 len= item->max_length; + + DBUG_ASSERT (item->result_type() == DECIMAL_RESULT); + + /* + 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 + */ + + const int required_length= + my_decimal_precision_to_length(intg + dec, dec, + item->unsigned_flag); + + overflow= required_length - len; + + if (overflow > 0) + dec= max(0, dec - overflow); // too long, discard fract + else + /* Corrected value fits. */ + len= required_length; + } + return new Field_new_decimal(len, item->maybe_null, item->name, + dec, item->unsigned_flag); +} + + int Field_new_decimal::reset(void) { store_value(&decimal_zero); -- cgit v1.2.1