How Do I Handle Apostrophes in SQL INSERT and SELECT Statements?

Insert values ​​containing apostrophes in SQL statements

Directly inserting values ​​containing apostrophes into SQL queries may cause errors. This is because apostrophes represent the beginning and end of strings in SQL. To solve this problem, the apostrophes need to be escaped.

For example, an apostrophe appears in the Last field of the Person table:

<code class="language-sql">Insert into Person
  (First, Last)
Values
  'Joe',
  'O'Brien'</code>

This syntax will cause an error because the apostrophe following the letter O will be interpreted as the end of the string value. To fix this, just double the apostrophe to escape it:

<code class="language-sql">INSERT INTO Person
    (First, Last)
VALUES
    ('Joe', 'O''Brien')</code>

The same principle applies to SELECT queries:

<code class="language-sql">SELECT First, Last FROM Person WHERE Last = 'O''Brien'</code>

This is because apostrophes are used to separate strings. When you want to use an actual apostrophe in a string, it needs to be escaped to prevent SQL from mistaking it for the end of the string.

However, it is worth noting that developers generally do not encounter this problem when writing code. Frameworks and tools often take care of escaping special characters and preventing SQL injection vulnerabilities.

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