SQL Server equivalent to MySQL's EXPLAIN
I was reading an SQL tutorial which used the keyword EXPLAIN to see how a query is executed.开发者_C百科 I tried it in SQL Server 2008 with no success.
How do I get the equivalent result?
I believe that the EXPLAIN
keyword is an MySQL concept - the equivalent Microsoft SQL server concept is the execution plan.
The simplest way of getting an execution plan is to turn on the "Show actual execution plan" menu item (in the query menu) in SQL server management studio. Alternatively you can read a more in-depth guide on execution plans here:
- http://www.simple-talk.com/sql/performance/execution-plan-basics/
This article goes into a lot more detail on what execution plans are, how to obtain an execution plan, and the different execution plan formats.
The MySql EXPLAIN statement can be used either as a synonym for DESCRIBE or as a way to obtain information about how MySQL executes a SELECT statement.
The closest equivalent statement for SQL Server is:
SET SHOWPLAN_ALL (Transact-SQL)
or
SET SHOWPLAN_XML (Transact-SQL)
From a SQL Server Management Studio query window, you could run SET SHOWPLAN_ALL ON
or SET SHOWPLAN_XML ON
and then your query. At that point It will not return the result set of the query, but the actual execution plan. When you then run SET SHOWPLAN_ALL OFF
or SET SHOWPLAN_XML OFF
and then run your query, you will then again get a result set.
In SSMS (I got 18.3.1) highlight the query in question and hit CTRL+L
(that does what Tobias mentioned - Query->Display Estimated Query Plan
)
Be aware that Microsoft added an EXPLAIN command to TSQL syntax in SQL 2012, however it only applies to Azure SQL Data Warehouse and Parallel Data Warehouse - so not the regular RDBMS product.
It provides an execution plan in XML format, and helpfully shows the parts of the plan that will be distributed across the warehouse nodes.
Source: TSQL EXPLAIN
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