允许您有条件地从多次比较中返回特定值。 有两种类型的 Case 语句: 简单Case 语句将某个表达式与一组简单表达式进行比较,以返回特定的值。 搜索Case 语句计算一组布尔表达式,以返回特定的值。 语法 Simple Case Statement CASE [input_expression] WHEN when_expression THEN when_true
sql case statement
select a, (case a when 1 then '中' else '国' end) AS B from table1 2.sqlserver字符串拆分(split)方法汇总 :http://www.cnblogs.com/aierong/archive/2008/11/19/sqlserver_split.html 二、WAITFOR WAITFOR { DELAY time | TIME time | (receive_statement) [TIMEOUT timeout] } 说明: DELAY 可...
SQL Server会拒绝执行该插入,并输出错误信息: Msg 547, Level 16, State 0, Line 2 The INSERT statement conflicted with the FOREIGN KEY constraint "FK_Order_Details_Orders".The conflict occurred in database "Northwind", table "Orders", column 'OrderID'. The statement has been terminated. 注意上...
运行以下查询以确定活动的 XEvent 或 Server 跟踪: SQL 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_num...
CASE statement based on TIME field case statement for count between two dates CASE statement in SQL returns Null CASE statement in WHERE clause for IS NULL: I want to say IS or IS NOT Null for a column using CASE Case Statement in Where clause with parameters SQL Server CASE statement incl...
SQL Server allows for only 10 levels of nesting inCASEexpressions. TheCASEexpression can't be used to control the flow of execution of Transact-SQL statements, statement blocks, user-defined functions, and stored procedures. For a list of control-of-flow methods, seeControl-of-Flow Language (...
(CASE WHEN statement_end_offset = -1 THEN LEN(CONVERT(nvarchar(max), text)) * 2 ELSE statement_end_offset END - statement_start_offset)/2) FROM sys.dm_exec_sql_text(sql_handle)) AS query_text FROM sys.dm_exec_query_stats ORDER BY [avg_cpu_cost] DESC ...
SQL Server整体性能分析 使用“性能监视器”查看使用情况。 Processor 查看CPU性能。 PhysicalDisk 查看IO情况。 Memory 查看内存情况。 SQLServer:Plan Cache 查看高速缓存使用情况。 SQLServer:Transactions 查看大事务使用情况。 SQLServer:Databases 查看数据库整体分析情况。
The 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' -- and smaller than 10000 as 'Small Order' ...