AND,&& Logical AND. Evaluates to 1 if all operands are nonzero and not NULL,to 0 if one or more operands are 0,otherwise NULL is returned.
AND,&&
Logical AND. Evaluates to 1 if all operands are nonzero and not NULL,to 0 if one or more operands are 0,otherwise NULL is returned.
operator precedence页也毫不矛盾.
