performance - IS MySQL logical operator XOR equivalent OR with negation -

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is there difference in results , performance between queries ?

select a.id table (c1 = 'value' xor c2 = 'value');  select a.id table (c1 != 'value' or c2 !='value');

xor not equivalent or negation. xor equivalent following logic:

where ((c1 = 'value' , c2 = 'value') or        (c1 <> 'value' , c2 <> 'value')        )

interestingly, second expression same as:

where not (c1 = 'value' , c2 = 'value')

i think should review boolean logic , truth tables.


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