如何将花括号添加到负值,这将是两列相减的结果,
假设我有三列
A B result(B-A)
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1 4 3
2 1 -1 [should be displayed as (1) not -1]
9 3 (6)
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total 3 5 (4)
如何在选择查询中执行此操作?