database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-07-30 16:24:05 +03:00
Code Activity

Fix for bug #43432: Union on floats does unnecessary rounding

Browse Source 
UNION could convert fixed-point FLOAT(M,D)/DOUBLE(M,D) columns  
to FLOAT/DOUBLE when aggregating data types from the SELECT  
substatements. While there is nothing particularly wrong with  
this behavior, especially when M is greater than the hardware  
precision limits, it could be confusing in cases when all  
SELECT statements in a union have the same  
FLOAT(M,D)/DOUBLE(M,D) columns with equal precision  
specifications listed in the same position.  
  
Since the manual is quite vague on what data type should be  
returned in such cases, the bug was fixed by implementing the  
most 'expected' behavior: do not convert FLOAT(M,D)/DOUBLE(M,D)  
to anything else if all SELECT statements in a UNION have the  
same precision for that column.
This commit is contained in:
Alexey Kopytov
2009-03-27 13:12:50 +03:00
parent 8725bcd944
commit afb2b6de68
5 changed files with 54 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
sql/mysql_priv.h
View File

@ -251,6 +251,11 @@ MY_LOCALE *my_locale_by_number(uint number);
#define PRECISION_FOR_DOUBLE 53
#define PRECISION_FOR_FLOAT 24
/* -[digits].E+## */
#define MAX_FLOAT_STR_LENGTH (FLT_DIG + 6)
/* -[digits].E+### */
#define MAX_DOUBLE_STR_LENGTH (DBL_DIG + 7)
/*
Default time to wait before aborting a new client connection
that does not respond to "initial server greeting" timely