Mysql搜索不为空的数据时

1、利用ISＮＯＴNULL 

SELECT columnID,columnName  FROM  hlq_info_info WHERE isDeleted = 0 AND title LIKE "第%" AND columnID  IS NOT NULL;

2、利用 != ''

SELECT columnID,columnName  FROM  hlq_info_info WHERE isDeleted = 0 AND title LIKE "第%" AND columnID != ''

3、利用 <>‘’

SELECT columnID,columnName  FROM  hlq_info_info WHERE isDeleted = 0 AND title LIKE "第%" AND columnI <>'';

当要求为空时

SELECT columnID,columnName  FROM  hlq_info_info WHERE isDeleted = 0 AND title LIKE "第%" AND columnID = ''

SELECT columnID,columnName  FROM  hlq_info_info WHERE isDeleted = 0 AND title LIKE "第%" AND ISNULL(columnID)

注意：

当条件是不登云空时，不能使用!= null

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Java程序员那些事