Invoice under counter cash sale

Yes...
You can prepare consolidated Invoices for the Cash Sale Invoice...

Sir is it mandatory to prepare daily single invoice for counter cash sale? and whether in GSTR1 : Document issued, we need to show invoice number of single invoice prepared for daily cash sale. 

No u cannot issue a consolidated invoice for day sale , there is no such provision in ACT, yes u can enter consolidated invoices for day in ur books of account by mentioning the bill no. from & to.

As section 31 CGSt Act
subclause 3(b)

b] a registered person may not issue a tax invoice if the value of the goods or services or both supplied is less than two hundred rupees subject to such conditions and in such manner as may be prescribed
In above said condtion of invoice below 200/- ,for such invoices in a day , u can make a consolidated one invocie

But if customer ask for bill even though it is below 200/- u r liable to issue him bill

ok sir so is it ok if in GSTR-1 only that invoice number i need to show of which I have issued invoice. 

Yes , Deep ji