@Select(" select case when b.counts is null then '0' else b.counts end as num,a.deptName as 'name' ,a.deptId from org_dept a " + " LEFT JOIN " + " (select count(1) as counts,deptId from rtc_call_log " + " where DATE_FORMAT(time_callercallout,'%Y-%m-%d') <![CDATA[>...
Left Join不管左表是否满足条件都输出,而右表只输出满足条件的行,其他行以null输出。Right Join和Left Join相反。Full Join同时输出左右表,对于满足条件的行,输出对应的左右表连接后的结果,对于不满足的行,输出左表(右表)的行,同时右表(左表)以null输出,相当于集合了Left Join和Right Join的特性。Cross Join没...
二、SQL LEFT JOIN 关键字 LEFT JOIN 关键字会从左表 (table_name1) 那里返回所有的行,即使在右表 (table_name2) 中没有匹配的行。即使右表中没有匹配,也会返回匹配结果为NULL。 SELECTcolumn_name(s)FROMtable_name1LEFTJOINtable_name2ONtablename1.column_name=table_name2.column_name; 绿色部分,为两...
具有空值的左键上的 SQL LEFT JOIN 是一种用于关联两个表的 SQL 查询操作。它会返回左表中所有的行,以及与右表中满足条件的行进行连接。 具体来说,LEFT JOIN 会将左表的每一行与...
EF Linq中的左连接Left Join查询 linq中的join是inner join内连接,就是当两个表中有一个表对应的数据没有的时候那个关联就不成立。比如表A B的数据如下 ?...from a in A join b in B on a.BId equals b.Id select new {a.Id, b.Id} 的结果是 {1,1} {2,2} {4,4} 因为3在B表中不...
= CASE WHEN (num_of_reads = 0 AND num_of_writes = 0) THEN 0 ` ELSE ((([num_of_bytes_read] + [num_of_bytes_written]) / (num_of_reads + num_of_writes)) / 1024) END, ` LEFT (mf.physical_name, 2) AS Volume, ` LEFT(DB_NAME (vfs.database_id),32) AS [Database Nam...
TRUNCATE(count(case when b.trade_status ='SUCCESS' then 1 else null end)*100/count(case when b.trade_status !='FAILED' then 1 else null end),2) rait from ifpay_ccpay.merchant a left join ifpay_ccpay.trade_info b on a.MERCHANT_ID=b.MERCHANT_NO ...
WHEN dept=3 THEN 'Art' ELSE 'None' END FROM teacher 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 处理NULL值 SELECT DISTINCT(party.name) FROM msp LEFT JOIN party ON (msp.party=party.code) WHERE msp.party IN (SELECT msp.party ...
if stock >= m then -- 库存足够 可以借出 set state = 1; -- 执行借书 -- 操作1:在借书记录表中添加记录 insert into records(snum,bid,borrow_num,is_return,borrow_date)values(a,b,m,0,sysdate()); -- 操作2: update books set book_stock = stock-m where book_id=b; else -- 库存不...