單個謂詞過濾：

= 基數計算公式 ：1/num_distinct*(num_rows-num_nulls),如果有直方圖，基數計算公式=(num_rows-num_nulls)*density

> 基數計算公式：(high_value-limit)/(high_value-low_value)*(num_rows-num_nulls)

>=基數計算公式：((high_value-limit)/(high_value-low_value)+1/num_distinct)*(num_rows-num_nulls) 因為有=，所以要加上=的選擇率，=的選擇率為1/num_distinct

< 基數計算公式：(limit-low_value)/(high_value-low_value)*(num_rows-num_nulls)

<=基數計算公式：((limit-low_value)/(high_value-low_value)+1/num_distinct)*(num_rows-num_nulls)

between ... and .... 的基數計算公式等價於 xxx<= high_limit ,xxxx>=low_limit

基數計算公式：((high_limit-low_limit)/(high_value-low_value)+2/num_distinct)*(num_rows-num_nulls)

low_limit< and < high_limit 基數計算公式：(high_limit-low_limit)/(high_value-low_value)*(num_rows-num_nulls)

low_limit<= and <high_limit 基數計算公式：(high_limit-low_limit)/(high_value-low_value)+1/num_distinct)*(num_rows-num_nulls)

雙謂詞，多謂詞

A AND B 選擇率計算公式=A選擇率*B選擇率

A OR B 選擇率計算公式=A+B-A AND B

NOT A 選擇率計算公式= 1- A選擇率