How SQL statements execute in SQL Server Management Studio with GO and without GO statement?
I have a simple query CREATE TABLE #tempTable (id int) DROP TABLE #tempTable CREATE TABLE #tempTable (id int) DROP TABLE #tempTable From my understanding, in the second part, it should create the #tempTable. But it shows the following error Msg 2714, Level 16, State 1, Line 4 There is already an object named '#tempTable' in the database. I have searched for the reason and found that it is because of a GO statement between the two part of the query. Therefore, the correct query is CREATE TABLE #tempTable (id int) DROP TABLE #tempTable GO CREATE TABLE #tempTable (id int) DROP TABLE #tempTable I have also found that GO just tells SSMS to send the SQL statements between each GO in individual batches sequentially. My question is, how are SQL statements executed? Is it not executed sequentially? If it executes sequentially, then why does my first query cause an error?
The SQL Server documentation does a pretty good job of explaining this. In your particular case, the issue is compile-time errors versus execution-time errors. How does this work? Without a GO separating the statements, all are compiled at the same time. The problem is that the third statement is a CREATE TABLE statement and the table already exists. All that is happened is that the statements are parsed and compiled. With the GO, the first two statements are compiled and executed. Voila! There is no table for the CREATE in the third statement.
The main reason of this error is that parsing the query occurs before executing the query. It happens because the whole code is executed as one batch. And SQL Server has one task to parse and execute. That's why a GO command (not a statement) allows you to avoid this problem. It signals the end of a batch. Here is a good topic to read about it: Understanding how SQL Server executes a query
SQL Server : Unable to edit data through SSMS
SQL multiple join reference table from different tables
How to update a list of different data to a table in sql server?
sql server decimal data type issue
SQL Server get closest timestamp (datetime) to hh:mm:ss (varchar) per row per day
SQL Server 2016 Mobile Report Datasets Expire about 30 Days
How can I remove older SQL Server instances?
How can I install MONDIAL on top of SQL Server?
I cannot insert or update after I have created trigger on a SQL Server table
Change data length using SSIS DerivedColumn
Spit graphical query plans as jpegs?
Calculate Nearest Neighbor in SQL Server
How to make dynamic scale for bar chart when chart inside a cell. SSRS 2012
Update table column for removing unwanted double quotes in SQL Server
Which DB driver to use DbVisualiser with Azure SQL?
How do you pass the property of an MVC controller into the where clause of a string literal query? [duplicate]