n指定数值的截断位数,规则如下:n值作用示例0截断小数部分trunc(123.456, 0) -> 123> 0 且未超出number_expr小数位数截断该小数位数往后的部分trunc(123.456...,负数向上取整trunc(123.456, 1.6) = trunc(123.456, 1); trunc(123.456, -1.2) = trunc(123.456, -1)null返回 null当不指定...n3",TRUNC('234.33333343',30) "n30",TRUNC('234.33333343',-2) "n-2",TRUNC('234.33333343',-20) "n-20",TRUNC...,负数向上取整trunc(123.456, 1.6) = trunc(123.456, 1); trunc(123.456, -1.2) = trunc(123.456, -1)null返回 null当不指定...n3",TRUNC('234.33333343',30) "n30",TRUNC('234.33333343',-2) "n-2",TRUNC('234.33333343',-20) "n-20",TRUNC