信贷额度关系credit-in（C_name，limit，Credit_balance）中的三个属性分别表示用户姓名、信贷额度和到目前为止的花费。下表为关系credit-in的一个具体实例。若要查询每个用户还能花费多少，相应的SQL语句应为：Select（）From credit-in。
- A.C_name，Credit_balance-limit
- B.C_name，limit-Credit_balance
- C.C_name，limit，Credit_balance
- D.C_name，Credit_balance
正确答案及解析
正确答案
解析
若要查询每个用户还能花费多少，需要给出每个用户的名字和花费，而花费应为limit-Credit_balance，因此，正确地SQL语句应为：
Select C_ name， limit-Credit_balance From credit-in
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