In order to get the decimal numbers, usually using a round function after the decimal point two remain in the oracle and mysql but can not take effect in sql server.
Another function used here cast (digitally format conversion):
the floating-point numbers into
select round (cast(20 as flocat)/7，4) //将20转为浮点数，再除以7，保留4位小数
In this way the use of decimal places can achieve the effect.
