--Identify which queries are the most costly by CPU
SELECT TOP 10
[Average CPU used] = total_worker_time / qs.execution_count
,[Total CPU used] = total_worker_time
,[Execution count] = qs.execution_count
,[Individual Query] = SUBSTRING (qt.text,qs.statement_start_offset/2,
(CASE WHEN qs.statement_end_offset = -1
THEN LEN(CONVERT(NVARCHAR(MAX), qt.text)) * 2
ELSE qs.statement_end_offset END - qs.statement_start_offset)/2)
,[Parent Query] = qt.text
,DatabaseName = DB_NAME(qt.dbid)
FROM sys.dm_exec_query_stats qs
CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) as qt
--WHERE DB_NAME(qt.dbid) = 'pnl' -- Filter on a given database.
ORDER BY [Average CPU used] DESC;
-- Total Reads by most expensive IO query
SELECT TOP 10
[Total Reads] = total_logical_reads
,[Total Writes] = total_logical_writes
,[Execution count] = qs.execution_count
,[Individual Query] = SUBSTRING (qt.text,qs.statement_start_offset/2,
(CASE WHEN qs.statement_end_offset = -1
THEN LEN(CONVERT(NVARCHAR(MAX), qt.text)) * 2
ELSE qs.statement_end_offset END - qs.statement_start_offset)/2)
,[Parent Query] = qt.text
,DatabaseName = DB_NAME(qt.dbid)
FROM sys.dm_exec_query_stats qs
CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) as qt
ORDER BY [Total Reads] DESC;
-- Total Writes by most expensive IO query
SELECT TOP 10
[Total Writes] = total_logical_writes
,[Total Reads] = total_logical_reads
,[Execution count] = qs.execution_count
,[Individual Query] = SUBSTRING (qt.text,qs.statement_start_offset/2,
(CASE WHEN qs.statement_end_offset = -1
THEN LEN(CONVERT(NVARCHAR(MAX), qt.text)) * 2
ELSE qs.statement_end_offset END - qs.statement_start_offset)/2)
,[Parent Query] = qt.text
,DatabaseName = DB_NAME(qt.dbid)
FROM sys.dm_exec_query_stats qs
CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) as qt
ORDER BY [Total Writes] DESC;
Tips 1.如何取得欄位中含有小數(非整數)的資料集
SELECT * FROM EXP_TABLE WHERE COLUMN_A > FLOOR(COLUMN_A)
Tips 2.亂數排序取回的資料集順序
SELECT *, NEWID() AS NEWID FROM EXP_TABLE ORDER BY NEWID
Tips 3.將yyyyMMddHHmmss轉換為DateTime型別
SELECT CONVERT(DATETIME, STUFF(STUFF(STUFF('20120511115720', 9, 0, ' '), 12, 0, ':'), 15, 0, ':'))
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