What is the string connection symbol in sql

The string connection symbol in SQL is two vertical bars (||), which is used to connect two strings. The connection result is the concatenation of strings.

String connection symbols in SQL

The symbols used to connect strings in SQL are two vertical line(||). This symbol means concatenating two strings together.

Grammar

字符串1 || 字符串2

Examples

SELECT '姓名: ' || 'John Doe'; -- 输出：姓名: John Doe

Notes

• If any string is NULL, the connection result is NULL.
• Connection symbols have higher precedence than arithmetic operators (such as and -). Therefore, arithmetic operations should be performed before concatenation.
• If you want to concatenate multiple strings, you can use parentheses to specify the concatenation order.

Other connection operations

In addition to the connection symbol, SQL also provides other functions for concatenating strings:

• CONCAT()Function: Equivalent to || symbol.
• CONCAT_WS()Function: Concatenate multiple strings and separate them using the specified delimiter. For example,CONCAT_WS(' ', 'Name:', 'John Doe')will output"Name: John Doe".

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