Summary: in this tutorial, you will learn how to use the SQL REPLACE function to search and replace all occurrences of a substring with another substring in a given string.. Introduction to the SQL REPLACE function. To assign a value other than the implicit default for the preceding statements, explicitly name the invisible column in the column list and provide a value for it. The whole string is returned along with the replacements. We are now using MySQL REPLACE function for a column of Books table using SELECT statement and will interchange the book name column string having a substring within the value to a new substring apply searching. Assuming your products table has the columns product_id, categories, and the new category_id:. select IFNULL(`prereq`,'') as ColumnName FROM test this query is selecting "prereq" values and if any one of the values are null it show an empty string as you like So, it shows all values but the NULL ones are showns in blank  However, in MySQL, the REPLACE is case-sensitive. Replace string Example With SELECT & WHERE statement. That is, the letter ‘C’ and ‘c’ has the same meaning. The above statement will replace all instances of ‘Old Company’ to ‘New Company’ in the field of company_name of client_table table. In MySQL, the REGEXP_REPLACE() function replaces occurrences of the substring within a string that matches the given regular expression pattern.. the input string doesn’t contain the substring), the the whole string is returned unchanged. DELIMITER $$ CREATE FUNCTION SPLIT_STRING(val TEXT, delim VARCHAR(12), pos INT) RETURNS TEXT BEGIN DECLARE output TEXT; SET output = REPLACE… As a note, if column is an int then you don't need to wrap the values in '' SELECT CASE WHEN column = 1 THEN 'ABC' WHEN column = 2 THEN 'DEF' WHEN column = 3 THEN 'GHI' WHEN column = 4 THEN 'JKL' END AS column FROM table WHERE column IN (1,2,3,4) Replace the empty values from a MySQL table with a specific value; MySQL query to replace a column value; Replace array value from a specific position in JavaScript; Swap a specific column value in MySQL; Replace a specific duplicate record with a new value in MySQL; Updating only a single column value in MySQL? Sometimes, you want to search and replace a substring with a new one in a column e.g., change a dead link to a new one, rename an obsolete product to the new name, etc. 5. Table Books: Code: select * from Books; This example shows using the REPLACE function with a table column. The following statement determines the highest sum of the arms and legs columns in the limbs table and assigns it to the @max_limbs variable: mysql>SELECT @max_limbs := MAX(arms+legs) FROM limbs; If there’s no match (i.e. There isn't a built-in MySQL trickery per se, but you can store a custom procedure that will accomplish your goal in a clever way. Following is the query to replace column value − mysql> update DemoTable set Score=95 where StudentId=3; Query OK, 1 row affected (0.12 sec) Rows matched : 1 Changed : 1 Warnings : 0. MySQL query to select column where value = one or value = two, value = three, etc? In MySQL 8.0.19 and later, you can specify the column values that REPLACE attempts to insert using VALUES ROW(). The REPLACE function is multibyte safe. The preceding SELECT statement assigns a column value to a variable, but variables also can be assigned values from arbitrary expressions. Using a table column with REPLACE function. To use REPLACE , you must have both the INSERT and DELETE privileges for the table. Note: The REPLACE function is case-insensitive in MS SQL Server. Another example for SQLECT query: SELECT REPLACE('www.mysql.com', 'w', 'Ww'); Above statement will return ‘WwWwWw.mysql.com’ as result.