Beginning SQL

The LENGTH() function takes just one argument, the string for which the length is required. So to find
out how long each member’s last name is, use the following query:
SELECT LastName, LENGTH(LastName)
FROM MemberDetails;
Remember to use LEN(), and not LENGTH(), if your database system is MS Access or SQL Server.
The query’s results are as follows:
LastName LENGTH(LastName)
Smith 5
Simons 6
Night 5
Jones 5
Jones 5
Johnson 7
Jackson 7
Hills 5
Hawthorn 8
Gee 3
Doors 5
Dales 5
Botts 5
The LENGTH() function is especially useful when used in combination with other functions. For example,
you can use it to make sure that the members’ surnames start with a capital letter. As it happens, all
the last names are correctly entered with capital letters, so you won’t see any difference. The following
example demonstrates the code converting strings to lowercase by using the LOWER() function so that
you can see the LENGTH() function actually working. In SQL Server, the code is as follows:
SELECT LastName, LOWER(SUBSTRING(LastName,1,1)) +
SUBSTRING(LastName,2,LEN(LastName) - 1)
FROM MemberDetails;
If you’re using MySQL, use the following code:
SELECT LastName, CONCAT(LOWER(SUBSTRING(LastName,1,1)),
SUBSTRING(LastName,2,LENGTH(LastName) - 1))
FROM MemberDetails;
Manipulating Data
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