Get your own SQL server

SQL Statement:

Result:

 product_id
------------
          1
          1
          2
          2
          3
          3
          4
          4
          5
          5
          6
          6
          7
          7
          8
          8
          9
          9
         10
         10
         11
         12
         13
         14
         15
         16
         17
         18
         19
         20
         21
         22
         23
         24
         25
         26
         27
         28
         29
         30
         31
         32
         33
         34
         35
         36
         37
         38
         39
         40
         41
         42
         43
         44
         45
         46
         47
         48
         49
         50
         51
         52
         53
         54
         55
         56
         57
         58
         59
         60
         61
         62
         63
         64
         65
         66
         67
         68
         69
         70
         71
         72
         73
         74
         75
         76
         77
(87 rows)
Demo Database:

categories
customers
products
orders
order_details
testproducts