select * from xx 出来的就是科学记数法 我现在把float的长度写成了9,取出来可以了 这个长度9是什么意思呢?
FLOAT[(M,D)] [UNSIGNED] [ZEROFILL] A small (single-precision) floating-point number. Allowable values are -3.402823466E+38 to -1.175494351E-38, 0, and 1.175494351E-38 to 3.402823466E+38. These are the theoretical limits, based on the IEEE standard. The actual range might be slightly smaller depending on your hardware or operating system. M is the total number of digits and D is the number of digits following the decimal point. If M and D are omitted, values are stored to the limits allowed by the hardware. A single-precision floating-point number is accurate to approximately 7 decimal places. 9应该是数字位数(长度)
出来的就是科学记数法
我现在把float的长度写成了9,取出来可以了
这个长度9是什么意思呢?
M是小数纵位数,D是小数点后面的位数。如果M和D被省略,根据硬件允许的限制来保存值。单精度浮点数精确到大约7位小数位。
desc了一下表,发现这个字段是float(9,0)
navicate在哪里编辑它的第二个值?
长度 9,2
2位小数