I have a table in which people have more than one record (they tend to be duplicates) and need to select only one record for each person. This could be done with a cursor but I believe there is a way to phrase a SELECT statement that will give me the desired result. The fields inv...
SELECT s.* FROM summary s WHERE s.ranks = 1 1. 2. 3. 4. 5. 6. 7. 8. 9. 所以给出通用方法: SELECT MIN(x.id), -- change to MAX if you want the highest x.customer, x.total FROM PURCHASES x JOIN (SELECT p.customer, MAX(total) AS max_total FROM PURCHASES p GROUP BY p....
Review recovery models and determine if you need to change it. https://learn.microsoft.com/sql/relational-databases/backup-restore/recovery-models-sql-server'asRecoveryModelChoiceselect'To truncate the log consider performing a transaction log backup on database '''+ @dbname+'''...
运行以下查询以确定活动的 XEvent 或 Server 跟踪: SQL复制 PRINT '--Profiler trace summary--'SELECTtraceid, property,CONVERT(VARCHAR(1024),value)ASvalueFROM::fn_trace_getinfo(default)GOPRINT'--Trace event details--'SELECTtrace_id,status,CASEWHENrow_number =1THENpathELSENULLendASpath,CASEWHENrow...
select a.name as '表名',b.rows as '表数据行数' from sysobjects a inner join sysindexes b on a.id = b.id where a.type = 'u' and b.indid in (0,1) --and a.name not like 't%' order by b.rows desc ---更改事务隔离级别,使用提交读快照,该模式下会读取事务已经提交更改后的数据...
1 TOP筛选 TOP选项是一个专有的T-SQL功能,用于限制查询返回的行数或行的百分比。 SELECT TOP (1) PERCENT orderid, orderdate, custid, empid FROM Sales.Orders ORDER BY orderdate DESC; 2 OFFSET-FETCH筛选 TOP选项不是标准SQL,且不支持跳过功能,OFFSET-FETCH是标准SQL,SQL Server2012时引入。
运行以下查询以确定活动的 XEvent 或 Server 跟踪: SQL复制 PRINT '--Profiler trace summary--'SELECTtraceid, property,CONVERT(VARCHAR(1024),value)ASvalueFROM::fn_trace_getinfo(default)GOPRINT'--Trace event details--'SELECTtrace_id,status,CASEWHENrow_number =1THENpathELSENULLendASpat...
DECLARE@init_sum_cpu_timeint, @utilizedCpuCountint--get CPU count used by SQL ServerSELECT@utilizedCpuCount =COUNT( * )FROMsys.dm_os_schedulersWHEREstatus='VISIBLE ONLINE'--calculate the CPU usage by queries OVER a 5 sec intervalSELECT@init_sum_cpu_time =SUM(cpu_time)FROMsys...
I have a result set of 500 rows, but this are for 100 invoice. I need only the top 10 of the last invoices. I found something like similar: How to select top 10 records from each category Sample data: InvNr | DetailLine 111 | 1 111 | 2 112 | 1 112 | 2 112 | 3 113 |...
First, it is important that your database be set to a compatibility level of at least 130. Next is the T-SQL code to view the current compatibility level that your current database is set to. SQLCopy SELECTd.compatibility_levelFROMsys.databasesasdWHEREd.name = Db_Name(); ...