It turned out that many entries in the table 1 and table 2 had string_field column with NULL values. I thought that JOIN would keep records with NULL values because NULL is equal to NULL, isn’t it? Then I tried
</isNotNull> 即使你在bean中不设置id的值，id的初始值也是0而不是null;所以这样配置a.id会等于0 而你把name变量用isNotNull这样配置，name如果不设置值，初始就是null,name的条件不就添加在sql中；isEqual相当于equals，数字用得多些，一般都是判断状态值 <isEqual property="state"compareValue="...
= (equals) ,<> (does not equal),!= (does not equal),> (is greater than),>= (is greater than or equal to),< (is less than),<= (is less than or equal to) - 比较条件。 可用于数字比较或字符串排序顺序比较。 对于数值比较,空字符串值(")被计算为0。 在任何相等比较中,NULL总是返...
/* In a unique secondary index we allow equal key values if they contain SQL NULLs 在唯一的二级索引中,如果包含sql NULL值 */ if (!index->is_clustered() && !index->nulls_equal) { for (i = 0; i < n_unique; i++) { if (dfield_is_null(dtuple_get_nth_field(entry, i))) { ...
执行表分区操作时,报错:start value of partition "xxx" NOT EQUAL up-boundary of last partition 重建索引失败 视图查询时执行失败 全局SQL查询 如何判断表是否执行过UPDATE或DELETE 执行业务报错“Can't fit xid into page” DWS元数据不一致-分区索引异常 对系统表gs_wlm_session_info执行TRUNCATE命令...
IsNull c# //判断是否为空,不为空为后面参数值SqlFunc.IsNull<TResult>(TResult thisValue, TResult ifNullValue)//判断是否为空,返回boolSqlFunc.IsNullOrEmpty(object thisValue) GreaterThan c# //大于SqlFunc.GreaterThan(object thisValue, object gtValue)//大于等于SqlFunc.GreaterThanOrEqual(object this...
這表示比較數據列時,兩個 NULL 值會被視為相等,與一般 EqualTo(=) 運算符不同。範例SQL 複製 > CREATE VIEW unknown_age AS SELECT * FROM person WHERE age IS NULL; -- Only common rows between two legs of `INTERSECT` are in the -- result set. The comparison between columns of the row ...
Understand how SQL NULLIF compares two values and returns NULL if they are equal. Learn syntax and examples for using NULLIF in SQL queries.
注意:因between 的范围是个闭区间(greater than or equal to low value and less than or equal to high value .), 故严格意义上应该再减去一个趋于0的小数,这里暂且设置成减去1秒(1/(24*60*60)),如果不要求这么精确的话,可以略掉这步。 七、对where语句的法则 ...
DELTA_DROP_COLUMN_AT_INDEX_LESS_THAN_ZERO、DELTA_INDEX_LARGER_OR_EQUAL_THAN_STRUCT、DELTA_INDEX_LARGER_THAN_STRUCT 42KD9 無法推斷數據表架構。 CANNOT_MERGE_SCHEMAS、COPY_INTO_SOURCE_SCHEMA_INFERENCE_FAILED、DELTA_FAILED_INFER_SCHEMA、UNABLE_TO_INFER_SCHEMA 42KDA 無法將檔案合併到數據表架構中。 DEL...