I am wondering whether its possible to extract two seperate columns of data after a 'THEN' statement when using CASE For example Select country, CASE WHEN X>1 Then (code which allows 'A' in one column and 'B' in a second column)... END
SELECTcolumn1, column2, ...CASEWHENcondition1THENresult1WHENcondition2THENresult2-- Add more WHEN conditions and results as neededENDASalias_nameFROMtable_name; We can add as manyWHEN ... THENconditions as required in theCASEstatement. For example, -- multiple CASE conditions in SQLSELECTcusto...
Update multiple columns and conditional updates with CASE statements The CASE statement can be used to conditionally update columns based on specific criteria. This allows for more granular control over which values are updated and under what circumstances, adding flexibility to SQL updates. For example...
报错:Update row with Key (id)=(xxxx) multiple times或者duplicate key value violates unique constraint 问题原因:违反唯一性约束,执行UPDATE、INSERT ON CONFLICT或INSERT操作时,主键存在重复数据。 解决方法: 若INSERT语法报错:可以改为INSERT INTO xx ON CONFLICT的语法,实现主键去重,详情请参见INSERT ON CONFLIC...
COUNT() function and SELECT with DISTINCT on multiple columns You can use the count() function in a select statement with distinct on multiple columns to count the distinct rows. Here is an example: SELECT COUNT(*) -- Count the number of rows in the result set ...
-- Loading the same field (empno) into multiple tables. -- -- TO RUN THIS CASE STUDY: -- 1. Before executing this control file, log in to SQL*Plus as -- scott/tiger. Enter @ulcase5 to execute the SQL script for -- this case study. This prepares and populates tables and ...
i've been researching this for two days and the answer is the same: yes, the rows seem to be ordered, but no, nobody can guarantee it. SQL Server is just the one actually breaking the rule really badly right now. Over on pep-249, we are ...
hive添加字段:alter table table_name add columns(columns_values bigint comment 'comm_text'); hive修改字段:alter table table_name change old_column new_column string comment 'comm_text'; 删除分区:alter table table_name drop partition(dt='2021-11-30'); ...
2.Which of the following methods is used for writing a query with columns from multiple tables?SELECT GROUP BY ORDER BY JOINSAnswer: D. Joins are used to connect multiple tables and project column data from multiple tables in Oracle.
小结:对于该 case, 索引效果[org_code,trade_date_time] > [trade_date_time, org_code]>[trade_date_time]。实际业务场景中,检索条件中 trade_date_time 基本上肯定会出现,但 org_code 却不一定,故索引的设计还需要结合实际业务需求。 优化Order by ...