What do you think of this piece of C code?
void foo(long v) { unsigned long u; unsigned sign; if (v < 0) { u = -v; sign = 1; } else { u = v; sign = 0; } ...
Seems pretty simple, right? Then what do you think of this output from MySQL:
mysql> create table t1 (a bigint) as select '-9223372036854775807.5' as a; mysql> select * from t1; +----------------------+ | a | +----------------------+ | -'..--).0-*(+,))+(0( | +----------------------+
Yes, that is authentic output from older versions of MySQL. Not just the wrong number, the output is complete garbage! This is my all-time favorite MySQL bug#31799. It was caused by code like the above C snippet.
So can you spot what is wrong with the code? Looks pretty simple, does it not? But the title of this post …
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