MySQL pesquisa mais rapida
Indices lose their speed advantage when using them in OR-situations:
SELECT * FROM a WHERE index1 = 'foo'
UNION
SELECT * FROM a WHERE index2 = 'baar';
is much faster than
SELECT * FROM a WHERE index1 = 'foo' OR index2 = 'bar';
SELECT * FROM a WHERE index1 = 'foo'
UNION
SELECT * FROM a WHERE index2 = 'baar';
is much faster than
SELECT * FROM a WHERE index1 = 'foo' OR index2 = 'bar';
Comentários
Postar um comentário