mysql> SELECT AM.AM_A, AM.AM_M FROM AM,AR,SA,MR,SM,SR WHERE AM.AM_A != SA.SA_A && AM.AM_A != AR.AR_A && AM.AM_M != MR.MR_M && AM.AM_M != SM.SM_M; <P>     mysql: Out of memory (Needed 8164 bytes)<P>
ERROR 2008: MySQL client run out of memory

or sometimes:
ERROR 1030: Got error 28 from table handler