How to replace text in a field in sql

There are two ways to replace field text in SQL: 1. REPLACE() function: replace the specified substring in the string; 2. UPDATE statement: use the CASE statement to replace field text based on conditions.

Two methods to replace text in a field in SQL

In SQL, you can use to replace text in a field Two methods: REPLACE() function and UPDATE statement.

1. REPLACE() function

The REPLACE() function is a function used in SQL to replace a specific substring in a string. The syntax is as follows:

REPLACE(string, search_string, replace_string)

Where:

• string: The string expression from which the substring is to be replaced.
• search_string: The substring to be replaced.
• replace_string: New string used to replace search_string.

Example:

Replace "New York" in the "City" column of the table "Customers" with "New City":

UPDATE Customers
SET City = REPLACE(City, 'New York', 'New City');

2. UPDATE statement

The UPDATE statement can also be used to replace Chinese characters in fields. Its syntax is as follows:

UPDATE table_name
SET column_name = CASE
    WHEN current_value = search_string THEN replace_string
    ELSE current_value
END
WHERE condition;

where:

• table_name: The name of the table to be updated.
• column_name: The column name to replace the text.
• current_value: The current value of the field.
• search_string: The substring to be replaced.
• replace_string: New string used to replace search_string.
• condition: Specifies the condition for which rows to update.

Example:

Replace "2023-03-01" in the "OrderDate" column in the table "Orders" with "2023-04-01":

UPDATE Orders
SET OrderDate = CASE
    WHEN OrderDate = '2023-03-01' THEN '2023-04-01'
    ELSE OrderDate
END
WHERE OrderDate = '2023-03-01';

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