【Java】mysql is NULL / is not NULL / = 'NULL' / != 'NULL'
2018-03-08 11:39
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如果在MySQL语句中，要对某个字段默认值进行判断是否为NULL，
只能用is NULL 或者 is not NULL
不可用 = 或者 != 进行判断
因为在mysql默认值中 NULL代表什么都没有，所以他不是字符串，
故不能用= 或者 != 判断
只能用is NULL 或者 is not NULL
不可用 = 或者 != 进行判断
因为在mysql默认值中 NULL代表什么都没有，所以他不是字符串，
故不能用= 或者 != 判断
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