how to use not last child in css code example

Example 1: how to use child selectors in css

ul li { margin: 0 0 5px 0; }
ul > li { margin: 0 0 5px 0; }

Example 2: parent and child link in mysql

table_children
parent child
0      0
1      1
2      2
3      3
4      4
0      1
0      2
0      3
0      4
1      2
1      3
1      4
3      4