What does the percent sign mean in sql

The percent sign (%) in SQL is a wildcard character that matches any number of characters. It can be used in: LIKE clause: compares data and patterns, and can indicate matching any number of characters. WHERE clause: Filter data rows and select rows that meet the conditions. It can match any number of characters. Other uses include comment lines and placeholders in prepared statements.

The percent sign (%) in SQL

In SQL, the percent sign (%) is A wildcard character that matches any number of characters. It can be used in the WHERE clause in LIKE and SELECT.

LIKE clause

The LIKE clause is used to compare data in a table with a given schema. The percent sign can be used in a pattern to indicate matching of any number of characters. For example:

<code>SELECT * FROM table_name WHERE name LIKE '%smith%';</code>

The above query will return all data rows that contain the "smith" string in the name column, regardless of their location.

WHERE clause

The WHERE clause is used to filter the data rows in the table and select only rows that meet the specified conditions. The percent sign can be used in the WHERE clause to match any number of characters. For example:

<code>SELECT * FROM table_name WHERE address LIKE '%street%';</code>

The above query will return all data rows that contain the "street" string in the address column, regardless of its position or surrounding characters.

Other uses

In addition to the LIKE and WHERE clauses, the percent sign can also be used in other SQL contexts, such as:

• Comment lines: Lines starting with two percent signs (%%) are considered comments and will not be executed.
• Placeholder: In prepared statements, the percent sign is used as a placeholder to instruct the SQL engine to substitute the value passed in.

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