SELECT IF(字段 IS NULL,0, 字段) as 重命名 From xxx SELECT IF(LENGTH(visit_no)>0,1,0) as 重命名 From xxx ...
SELECT IF AVG 字段 IS NULL, , 字段 as 重命名 Fromxxx ...
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SELECT IF(字段 IS NULL,0, 字段) as 重命名 From xxx SELECT IF(LENGTH(visit_no)>0,1,0) as 重命名 From xxx ...
SELECT IF(AVG(字段) IS NULL,0, 字段) as 重命名 From xxx ...
("use_tool=8 AND tk_roomId is null")->select(); ...
查询mysql 中某字段为空值的数据,于是写成了下面的样式,但返回的结果跟想要的不一样 错误:SELECT coupon_id FROM `t_coupon_info` WHERE remains_num = "" 正确:SELECT coupon_id FROM `t_coupon_info ...
在mysql中,查询某字段为空时,切记不可用 = null,而是 is null,不为空则是 is not null select * from table where column is null; select * from table where column is not null; ...
在mysql中,查询某字段为null空时,切记不可用 = null,而是 is null,不为空则是 is not null 而不是 != null select * from table where column is null ...
oracle select nvl(字段名,0) from 表名; sqlserver select isnull(字段名,0) from 表名; mysql select ifnull(字段名,0) from 表名; ...