原因:in在查询的时候,先查子查询的表B,然后将内表和外表做一个笛卡尔积,然后按照条件筛选,所以子查询表比较小的时候,in的速度较快; 而exists 是对外表A做loop循环,每次loop循环再对内表B进行查询,即我们先查询的不是子查询B的内容,而是查我们的主查询的表A,所以子查询表数据比较大的时候,exists的速度较快 n...
I need to use a loop in Transact (T-SQL), but it seems there’s no FOR loop construct in Microsoft SQL Server. How can I write a loop in my SQL scripts? Can you provide a loop example with a SELECT statement including begin, loop counter and end conditional logic that can be used...
DECLARE @loop INT; DECLARE @AccountDescription VARCHAR(50); DECLARE @AccountKey INT; DECLARE @AccountType VARCHAR(50); DECLARE @AccountCode INT; SELECT @loop = 0 BEGIN TRANSACTION WHILE (@loop < 300000) BEGIN SELECT @AccountKey = CAST(RAND() * 10000000 AS INT); SELECT @AccountDescription...
A Nested Loop join may also use the prefetch optimization, and this causes the same locking behavior. Lock escalation cannot occur if a different SPID is currently holding an incompatible table lock. Lock escalation always escalates to a table lock, and never to page locks. Additionall...
Can we use While loop in CTE? can we write DDL command in Stored Procedure? Can wildcards be used on datetime column? can you add colour to a fields output in T-SQL? Can you change the value of yes or no instead of true or false use data type (BIT) ? Can you have a TRY CATC...
DECLARE @loop INT; DECLARE @AccountDescription VARCHAR(50); DECLARE @AccountKey INT; DECLARE @AccountType VARCHAR(50); DECLARE @AccountCode INT; SELECT @loop = 0 BEGIN TRANSACTION WHILE (@loop < 300000) BEGIN SELECT @AccountKey = CAST(RAND() * 10000000 AS INT); SELECT @AccountDescription...
In a distributed transaction, execute_statement cannot be issued against a loopback linked server when the connection has multiple active result sets (MARS) enabled. If execute_statement returns data with the READTEXT statement, each READTEXT statement can return a maximum of 1 MB (1024 KB) of...
First check [x ] I added a very descriptive title to this issue. [ x] I used the GitHub search to find a similar issue and didn't find it. [ x] I searched the FastAPI documentation, with the integrated search. [x ] I already searched in ...
Error in ForEach Loop - "User::FullResultSet" does not contain a valid data object Error in SSIS while Loading data Error in Visual Studio 2017 Integration Services project: Unable to start debugging. The debugger is not properly installed. Error loading 'Microsoft.SqlServer.DTSRuntimeWrap' or ...
What this code does is add a retry using a WHILE loop. I set the number of retries to three, but that's configurable. The bottom line is that now we have a way to retry a deadlock victim's code from within T-SQL–something we've never been able to do before. ...