用具体列名替代星号
写SQL语句时，我们尽量使用具体列名来替换星号(*)，虽然效能上微不足道，但写了，实际上已经是另外的境界了。 比如很多时候，我们都会这样写：
写SQL语句时，我们尽量使用具体列名来替换星号(*)，虽然效能上微不足道，，但写了，实际上已经是另外的境界了。
比如很多时候，我们都会这样写：
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