sql case statement
SQL SUM With GROUP BY SQL JOINS SQL CASEThe SQL CASE statement evaluates a list of conditions and adds a column with values based on the condition. For example, -- add a new column 'order_volume' in the Orders table -- and flag any order greater than 10000 as 'Large Order' -- ...
1.CASE 写法如下: CASE WHEN condition1 THEN result1 WHEN condition2 THEN result2 WHEN conditionN THEN resultN ELSE result END; 解释:1)先匹配第一条,不匹配的话继续第二条,如此循环,
Staff=CASE WHEN [JobTitle]LIKE'%chief%'OR[JobTitle]LIKE'%vice president%'THEN'Upper Management'WHEN [JobTitle]LIKE'%manager%'THEN'Middle Management'WHEN [JobTitle]LIKE'%senior%'THEN'Senior Staff'ELSE'Staff'END,StaffCount=COUNT(CASE WHEN [JobTitle]LIKE'%chief%'OR[JobTitle]LIKE'%vice presid...
SQL Server offers two functionsCOUNTandCOUNT_BIGwhich can get a count of rows. Both functions can be used with a SELECT statement including WHERE, HAVING, GROUP BY, and ORDER BY clauses. The COUNT function will return the result as an int (4 bytes) whereas the COUNT_BIG function will re...
CASE WHEN 和COUNT CASE WHEN 和SUM CASE WHEN 和 AVG函数 与AVG函数结合,可实现计算百分比的功能 部分例子参考来自:https://www.sqlshack.com/case-statement-in-sql 你的点赞是我持续更新的动力~ 谢谢 Thanks♪(・ω・)ノ SQL学习笔记 友情链接: Y:SQL学习笔记 - 窗口函数OVER19 赞同 · 0 评论...
3、sqltoy的分页取总记录的过程不是简单的select count(1) from (原始sql);而是智能判断是否变成:select count(1) from 'from后语句',并自动剔除最外层的order by 4、sqltoy支持并行查询:parallel="true",同时查询总记录数和单页数据,大幅提升性能 5、在极特殊情况下sqltoy分页考虑是最优化的,如:with t1 as ...
CASEWHENrow_number =1THENstop_timeELSENULLendASstop_time, max_files, is_rowset, is_rollover, is_shutdown, is_default, buffer_count, buffer_size, last_event_time, event_count, trace_event_id, trace_event_name, trace_column_id, trace_column_name, expensive_eventFROM(SELECTt.idAStrace_id...
CASE表达式是用来判断条件的,条件成立时返回某个值,条件不成立时返回另一个值。 语法: CASEWHENComparsionConditionTHENresultWHENComparsionConditionTHENresultELSEotherEND (注:各分支返回的数据类型需一致。) (注:when子句一定要有排他性,因为当when子句为真时,剩余的when子句会被忽略。) ...
Filter for groups using COUNT() with GROUP BY and HAVING In example 4, we see that COUNT() can be used with GROUP BY. We can use the HAVING statement to filter for groups using the number of rows in that group. For example, to find the number of years that have less than 50 prod...