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SQL | Temporary tables and table variables exercise | Temporary tables - first letter count of events
This exercise is provided to allow potential course delegates to choose the correct Wise Owl Microsoft training course, and may not be reproduced in whole or in part in any format without the prior written consent of Wise Owl.
You can learn how to do this exercise if you attend one of more of the courses listed below!
| Software ==> | SQL (198 exercises) |
| Version ==> | Any version of SQL Server |
| Topic ==> | Temporary tables and table variables (9 exercises) |
| Level ==> | Relatively easy |
| Classroom ==> | Fast-track SQL / Advanced SQL |
| Online ==> | Fast-track SQL / Advanced SQL |
- Go into SQL Server Management Studio;
- Open the SQL file you've just unzipped (you can press CTRL + O to do this); then
- Execute this script.
This will generate the database that you'll need to use in order to do this exercise (note that the database and script are only to be used for exercises published on this website, and may not be reused or distributed in any form without the prior written permission of Wise Owl).
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Using the INTO syntax, create a temporary table holding a count of the number of event names beginning with the same letter.
Use LEFT to return only the first letter from the EventName column, then GROUP BY this and perform a COUNT.
The problem with INTO is that it decides the data type of the column based on the current data. Try adding XZ as a first letter with a count of 57 using INSERT INTO:
-- Trying to add this data gives an error
INSERT INTO #EventsByLetter
values ('xz', 57)
This should generate an error:
The original data type is too small.
Add a statement at the top of your query to create a new table called #EventsByLetter with two columns:
| Column | Type |
|---|---|
| First letter | varchar(2) |
| Number of events | int |
Now change your SELECT statement so that it adds the first letter summary rows into this table, rather than creating a new table. The syntax of the command to insert rows into an existing table looks something like this:
INSERT INTO TableName (
Column1,
...,
ColumnN
)
SELECT (
Value1,
...,
ValueN
)
FROM ...
When you run this revised query, it should accommodate the xz insertion also, and allow you to display the final results:
Use ORDER BY to put the results into alphabetical order by the First Letter column.
Optionally save this as Tables of Temp-tation.sql, then close it down.