When and How Should I Use Backticks in SQL?

Usage of backtick (`) in SQL

Although the backtick (`) is widely used, it has no special meaning in the SQL standard.

Identifier reference

The SQL standard requires the use of double quotes to quote identifiers:

SELECT "select" FROM "from" WHERE "where" = "group by";

MySQL Usage

In MySQL, backticks can be used as an alternative to double quotes to quote identifiers:

SELECT `select` FROM `from` WHERE `where` = `group by`;

Other databases

Various databases handle identifier references differently:

• MS SQL Server: Use square brackets []
• Informix: You can use double quotes or single quotes; the specific behavior is controlled by environment variables
• DB2: Only supports standard notation using single quotes
• SQLite: seems to follow standards
• Oracle: Seems to follow standards
• Sybase: Allow double quotes or square brackets

When to quote identifiers

Normally, identifiers should not be quoted unless absolutely necessary. Some common scenarios that require citation include:

• When the identifier matches a keyword in the SQL version being used
• When upgrading the server, column names that were not keywords before become keywords
• When used for demonstration purposes in extreme cases

Quotation usage of values ​​and field names

Values ​​must always be enclosed in single quotes:

SELECT * FROM table WHERE field = 'value';

Field names can be enclosed in double or single quotes, but this is not mandatory:

SELECT "field" OR field FROM table;

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