What does the percent sign mean in sql

The percent sign (%) in SQL is a wildcard character representing any number of characters, mainly used for string comparison and fuzzy queries: String comparison: used to match character sequences that begin with a specific string. Fuzzy query: Used to match fields in a table that contain a specific sequence of characters, regardless of the remainder of the field. Regular expressions: Can be used with regular expressions in some databases to match strings with specific patterns.

The percent sign (%) in SQL

The percent sign (%) character in SQL is Wildcard character, representing any number of characters. It is mainly used for string comparison and fuzzy query.

Usage:

• String comparison:

  • For example,LIKE 'test%'will match all strings starting with "test", such as "test123", "test_abc".

• Fuzzy query:

  • For example,SELECT * FROM table WHERE name LIKE '%john%'Will match all name fields containing "john" in the table, such as "John Doe", "John Smith".

• Regular Expressions:

  • In SQL Server, the percent sign can also be used in regular expressions. (Other database systems may use different syntax)
  • For example,REGEXP_LIKE('12345%', '45$')will match a string ending with "45".

Note:

• The percent sign does not match specific characters such as spaces.
• If you want to match actual percent signs, you need to use escape characters (for example,LIKE '100\%').

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