WISE OWL EXERCISES
- Simple Queries (4)
- Setting criteria using WHERE (5)
- Calculations (7)
- Calculations using dates (4)
- Basic joins (8)
- More exotic joins (2)
- Aggregation and grouping (8)
- Views (5)
- Subqueries (3)
- Stored procedures (5)
- Variables (8)
- Parameters and return values (11)
- Testing conditions (1)
- Looping (3)
- Scalar functions (6)
- Transactions (4)
- Creating tables (4)
- Temporary tables and table variables (9)
- Table-valued functions (6)
- Derived tables and CTEs (11)
- Dynamic SQL (4)
- Pivots (2)
- Triggers (2)
- Archived (70)
SQL | Archived exercise | Error trap when creating temp table
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If you haven't already done so, run the stored procedure in the above folder to generate a database of training courses and delegates.
Create a query to show all the people with really long names - similar to the following - and run it twice:
You should find that this displays only 3 people
When you run your query a second time, it should crash because the temporary table #BigPeople already exists. Apply error trapping at the top of the query such that:
- Your query attempts to delete the table
- If it already exists, the table is deleted and your query prints out a message saying that this has happened
- If it didn't already exist, you get a message saying that nothing was deleted
You can test out that this final possibility works by adding the following command at the end of your query:
This command would ensure that the table didn't exist the next time that you run the query
Optionally, save this query as Check deleting temp table.sql, then close it down.