That CONCAT works with NULL columns as well as empty columns. If you are using a really sad library to connect to MySQL, you may need to give the column an alias (. 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) INSERT INTO `crs_student` VALUES (2, 'Bartholomew', 'Barclay', NULL, 1) INSERT INTO `crs_student` VALUES (1, 'Anthony', 'Abbot', 'J', 1)
UCASE () Synonym for UPPER () UNHEX () Return a string containing hex representation of a number. Note: In CockroachDB v20.2 and earlier, for all values other than STRING. TRIM () Remove leading and trailing spaces. Concatenation between a non- NULL value and a NULL value results in a NULL value. TOBASE64 () Return the argument converted to a base-64 string. ) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci Return a substring from a string before the specified number of occurrences of the delimiter. `year` decimal(1,0) unsigned NOT NULL default '0', The operator is the concatenation in SQLite. 'Coalesce' is the ANSI-standard function name, but ISNULL is easier to spell. The importance of TomCerul's comment is worthy rewriting or at least editing the correct answer. SET Concatenated ISNULL (Column1, '') + ISNULL (Column2, '') If the value of the column/expression is indeed NULL, then the second value specified (here: empty string) will be used instead. Then you get to figure out what you want to do if both were null. `initials` varchar(4) collate latin1_general_ci default NULL, That will give you a response if one or both fields are null. `last_name` varchar(40) collate latin1_general_ci NOT NULL default '', `first_name` varchar(40) collate latin1_general_ci NOT NULL default '',
Mysql concat fails on null archive#
If the data you need to attach is more than 3MB, you should create a compressed archive of the data and a README file that describes the data with a filename that includes the bug number (recommended filename: mysql-bug-data-7533.zip) and upload one to.
`student_id` smallint(5) unsigned NOT NULL default '0', CONCAT fails if one of the columns is NULL. I have a MyISAM tables constructed as follows:ĬREATE TABLE IF NOT EXISTS `crs_student` ( Two things: First: Change GROUPCONCAT (rs.categoryid, ',') to GROUPCONCAT (rs.categoryid) The comma is the default separator, from the docs you can see that if you want to change the separator that would be something like GROUPCONCAT (rs.categoryid SEPARATOR '') Second: Remove the last: GROUP BY rs.categoryid.
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