SQL Server 2017

By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.

select @@version;


(No column name)


Microsoft SQL Server 2017 (RTM-CU12) (KB4464082) - 14.0.3045.24 (X64) 
	Oct 18 2018 23:11:05 
	Copyright (C) 2017 Microsoft Corporation
	Express Edition (64-bit) on Windows Server 2012 R2 Standard 6.3 <X64> (Build 9600: ) (Hypervisor)



create table t(rowid int, name varchar(100),shares_bought int, date_val date)
insert into t
select *
from (values (1,'Dan',2,'2018-08-23')
            ,(2,'Mirko',1,'2018-08-25')
            ,(3,'Shuli',3,'2018-05-14')
            ,(4,'Regina',1,'2018-01-19')
            )t(x,y,z,a)
4 rows affected

    with generate_data
      as (select top (select max(shares_bought) from t)
                 row_number() over(order by (select null)) as rnk /* This would generate rows starting from 1,2,3 etc*/
           from sys.objects a
           cross join sys.objects b
       )
    select row_number() over(order by t.rowid) as rowid,t.name,1 as shares_bought,t.date_val
      from t 
      join generate_data gd
        on gd.rnk <=t.shares_bought /* generate rows up and until the number of shares bought*/
        order by 1


rowid
name
shares_bought
date_val


1
Dan
1
23/08/2018 00:00:00

2
Dan
1
23/08/2018 00:00:00

3
Mirko
1
25/08/2018 00:00:00

4
Shuli
1
14/05/2018 00:00:00

5
Shuli
1
14/05/2018 00:00:00

6
Shuli
1
14/05/2018 00:00:00

7
Regina
1
19/01/2018 00:00:00

rowid	name	shares_bought	date_val
1	Dan	1	23/08/2018 00:00:00
2	Dan	1	23/08/2018 00:00:00
3	Mirko	1	25/08/2018 00:00:00
4	Shuli	1	14/05/2018 00:00:00
5	Shuli	1	14/05/2018 00:00:00
6	Shuli	1	14/05/2018 00:00:00
7	Regina	1	19/01/2018 00:00:00