logical and operator

基本解释

Consider using parentheses to improve readability and avoid mistakes because of logical operator precedence.
考慮使用括號來改善可讀性和避免由於邏輯操作符的優先級導致的錯誤。
A logical operator that consists of a logical AND followed by a logical NOT and returns a false value only if both operands are true.
由邏輯與和其後的邏輯非組成的邏輯運算符，如果兩個運算域都是真，則返廻的值便爲假。
It's best to read such execution plans from the left-lowest operator in the tree, since the logical flow in the plan is from bottom to top and left to right.
因爲執行計劃中的邏輯流是自下而上、從左到右，所以看此類執行計劃時，最好是從樹中左下方的操作符開始。