小编san*_*osh的帖子

如何在 MySQL 的同一列上计数和检索 null 和 not null？

我的表

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id   |    name    |      visited   |   registDate |
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1    |    george  |       NULL     |   2014-04-01 |
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2    |    Thomas  |       NULL     |   2014-04-15 |
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3    |    Wilfred |        1       |   2014-04-24 |
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4    |    paul    |        1       |   2014-04-10 |
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5    |    elina   |       NULL     |   2014-05-03 |
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6    |    angela  |       NULL     |   2014-04-13 |
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7    |    elina   |        1       |   2014-05-18 | …