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Code:
sample table (T_students)
ID grade suname name tel
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1 1 A A' 1111-11-1111
2 2 B B' 2222-22-2222
3 3 A A'' 1111-11-1111
4 4 B B'' 2222-22-2222
5 5 A A''' 1111-11-1111
6 6 D D' 3333-33-3333
expected result
ID grade suname name tel bro_sis_grade1 bro_sis_name1 bro_sis_grade2 bro_sis_name2 bro_sis_grade3 bro_sis_name3
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1 1 A A' 1111-11-1111 3 A'' 5 A'''
2 2 B B' 2222-22-2222 4 B''
3 3 A A'' 1111-11-1111 1 A' 5 A'''
4 4 B B'' 2222-22-2222 2 B'
5 5 A A''' 1111-11-1111 1 A' 3 A''
6 6 D D' 3333-33-3333