So, when there is a value in the column that is not null, that will be concatenated. The COALESCE function returns the first non-Null value. To avoid this, you can use the COALESCE function. That CONCAT works with NULL columns as well as empty columns. When you concatenate any string with a NULL value, it will result in NULL. If I change the initials column to NOT NULL default "" then it works correctly.Ĭreate table with sample data using above code, then try the SELECT statement. If I remove the initials column from the CONCAT statement then student_name is constructed correctly. SELECT student_id, CONCAT(first_name, " ", initials, " ", last_name) AS student_name, year FROM crs_student WHERE (student_id='1') OR (student_id='2') OR (student_id='3') INSERT INTO `crs_student` VALUES (3, 'Christopher', 'Carter', NULL, 1) UCASE () Synonym for UPPER () UNHEX () Return a string containing hex representation of a number. TRIM () Remove leading and trailing spaces. TOBASE64 () Return the argument converted to a base-64 string. If it's null, replace the NULL with an empty string, and then concatenate that expression to the name column. INSERT INTO `crs_student` VALUES (2, 'Bartholomew', 'Barclay', NULL, 1) Return a substring from a string before the specified number of occurrences of the delimiter. You can concatenate the parens and the nickname, and then use the IFNULL to check to see if the result of that expression is NULL. INSERT INTO `crs_student` VALUES (1, 'Anthony', 'Abbot', 'J', 1) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci I'm trying to add link to my image when I return it from database but I don't want to add it when image is null. `year` decimal(1,0) unsigned NOT NULL default '0', This would also only put one space if there was no middle name and a space before and after if there was a middle name. Like so: SELECT CONCAT (fName1,COALESCE (CONCAT (' ',mName2,' '),' '),lName3) AS userName FROM users WHERE level > 10. `initials` varchar(4) collate latin1_general_ci default NULL, you could also the COALESCE () function to return the first non-null value. Does work too, or will I have to modify my code Or is there any other solution I'm coding in Ruby on Rails 3.1, by the way. I'd normally use concat() to concatenate in MySQL. Those records do not end up with an Update field. `last_name` varchar(40) collate latin1_general_ci NOT NULL default '', At some later date I'd like to shift to MySQL, and hence it would be nice if no changes to the code had to be made. I am doing a simple Update on a table whereby I concat three fields: Update TableA concat (Field1,Field2,Field3) The issue is that in some records one or more of the fields can be NULL. `first_name` varchar(40) collate latin1_general_ci NOT NULL default '', `student_id` smallint(5) unsigned NOT NULL default '0', I have a MyISAM tables constructed as follows:ĬREATE TABLE IF NOT EXISTS `crs_student` (
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