随笔分类 - mysql
摘要：如下，可以看到使用后，也统计了null的个数。
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摘要：mysql> select * from table1; +----------+------------+-----+---------------------+ | name_new | transactor | pid | order_date | +----------+------------+-----+---------------------+ | 1hah...
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摘要：mysql> select * from table1; +----------+------------+-----+---------------------+ | name_new | transactor | pid | order_date | +----------+------------+-----+---------------------+ | 1hah...
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摘要：mysql> select * from table1; +----------+------------+-----+---------------------+ | name_new | transactor | pid | order_date | +----------+------------+-----+---------------------+ | 1hah...
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摘要：mysql> select * from table1; +----------+------------+-----+---------------------+ | name_new | transactor | pid | order_date | +----------+------------+-----+---------------------+ | 1hah...
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摘要：mysql> select * from table1; +----------+------------+-----+---------------------+ | name_new | transactor | pid | order_date | +----------+------------+-----+---------------------+ | 1hah...
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摘要：mysql> select * from table1 where minute(order_date)=46; +----------+------------+-----+---------------------+ | name_new | transactor | pid | order_date | +----------+------------+-----+-...
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摘要：mysql> select * from table1; +----------+------------+-----+---------------------+ | name_new | transactor | pid | order_date | +----------+------------+-----+---------------------+ | 1hah...
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摘要：mysql> select tan(pi()/4); +--------------------+ | tan(pi()/4) | +--------------------+ | 0.9999999999999999 | +--------------------+ 1 row in set (0.00 sec)
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摘要：mysql> select pi(); +----------+ | pi() | +----------+ | 3.141593 | +----------+ 1 row in set (0.00 sec)
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摘要：mysql> select mod(16,3); +-----------+ | mod(16,3) | +-----------+ | 1 | +-----------+ 1 row in set (0.00 sec)
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摘要：mysql> select sqrt(16); +----------+ | sqrt(16) | +----------+ | 4 | +----------+ 1 row in set (0.00 sec)
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摘要：mysql> select sin(PI()/6); +---------------------+ | sin(PI()/6) | +---------------------+ | 0.49999999999999994 | +---------------------+ 1 row in set (0.00 sec)
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摘要：mysql> select abs(3-5); +----------+ | abs(3-5) | +----------+ | 2 | +----------+ 1 row in set (0.00 sec)
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摘要：mysql> select exp(1); +-------------------+ | exp(1) | +-------------------+ | 2.718281828459045 | +-------------------+ 1 row in set (0.00 sec)
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摘要：mysql> select rand(); +--------------------+ | rand() | +--------------------+ | 0.9913473352709294 | +--------------------+ 1 row in set (0.00 sec) mysql> select rand()*100; +--------...
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摘要：mysql> select * from table1; +----------+------------+-----+---------------------+ | name_new | transactor | pid | order_date | +----------+------------+-----+---------------------+ | 1hah...
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摘要：alter table table1 add order_date datetime null; mysql> select * from table1; +----------+------------+-----+------------+ | name_new | transactor | pid | order_date | +----------+------------+...
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摘要：参考： https://www.yiibai.com/mysql/mysql_function_addtime.html
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