Tag: sql

MySQL length() vs char_length()

Posted on by Ian

In MySQL, there are many times where the length() function and the char_length() function will provide exactly the same results. However, there are also times where the results will be completely different. Here’s why.

First, here’s the definition for each of these functions:

char_length()
Returns the length of a string, measured in characters.
length()
Returns the length of a string, measured in bytes.

Notice “characters” vs “bytes” – one is measured in characters, the other is measured in bytes.

In many cases, the number of bytes will be the same as the number of characters in the string, but this isn’t always the case. The number of bytes used per character depends on how the data is stored. For example, if the string is stored as Unicode data, there will be 2 bytes per character.
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What is LENGTH() in MySQL?

Posted on by Ian

One of the many functions in MySQL is the LENGTH() function, which returns the length of a string, measured in bytes.

Example:

SELECT LENGTH('Lit');

Result:

+---------------+
| LENGTH('Lit') |
+---------------+
|             3 |
+---------------+

This is a simple example and the result is the same as if we’d used the CHAR_LENGTH() function. However, the LENGTH() function can return different results, depending on the data type.
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T-SQL vs SQL

Posted on by Ian

Here’s a quick overview of the difference between SQL and T-SQL (Transact-SQL). Not so much the differences as such, but more an explanation of T-SQL and where it sits in relation to SQL.

If you’ve done any database development or administration, you’re probably familiar with SQL. SQL, which stands for Structured Query Language, is a standard query language for working with databases. Most of the major relational database management systems such as MySQL, Oracle, SQL Server, PostgreSQL, etc support SQL in one way or another.

However, while the SQL standard provides clear specifications, it also allows for database vendors to add their own extensions. This allows vendors to provide extra features and functionality for their customers that might not be offered by their competitors.

This is where T-SQL comes in.

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