ADD column if none exists in MySQL
mysql add column if not exists
see if column exists mysql
mysql drop column if exists
mysql add column with default value
alter table if exists mysql
mysql rename column
mysql alter table add column after
I figure this is very easy, but I am trying to run this command only if those columns already don't exist:
ALTER TABLE `surveytable` ADD IF NOT EXISTS Survey_Name_Qualtrics VARCHAR(20); ALTER TABLE `surveytable` ADD IF NOT EXISTS Survey_URL_Qualtrics VARCHAR(600);
CREATE PROCEDURE addcol() BEGIN IF NOT EXISTS( SELECT * FROM information_schema.COLUMNS WHERE COLUMN_NAME='new_column' AND TABLE_NAME='the_table' AND TABLE_SCHEMA='the_schema' ) THEN ALTER TABLE `the_schema`.`the_table` ADD COLUMN `new_column` bigint(20) unsigned NOT NULL default 1; END IF; END; delimiter ';' CALL addcol(); DROP PROCEDURE addcol;
This is the code that i use, i dont think you can use if not exists on a ALTER column.
An alternative you can watch for the error you get if you try to insert a column that already exists, i think its 1062. And handle the error.
Of course the better way is to not get the error in the first place.
How to Add Columns To A Table Using MySQL ADD COLUMN, This tutorial shows you how to use MySQL ADD COLUMN statement to add one However, there is no statement like ADD COLUMN IF NOT EXISTS available. CREATE PROCEDURE addcol() BEGIN IF NOT EXISTS( SELECT * FROM information_schema.COLUMNS WHERE COLUMN_NAME='new_column' AND TABLE_NAME='the_table' AND TABLE_SCHEMA='the_schema' ) THEN ALTER TABLE `the_schema`.`the_table` ADD COLUMN `new_column` bigint(20) unsigned NOT NULL default 1; END IF; END; delimiter ';' CALL addcol(); DROP PROCEDURE addcol;
This is all over the internet. Basic idea is to check the system table
INFORMATION_SCHEMA.COLUMNS for your column. I'm assuming "none exists" applies to the name of the column only.
MySQL 8.0 Reference Manual :: 13.1.9 ALTER TABLE , If all columns that make up an index are dropped, the index is dropped as well. If you use CHANGE or MODIFY to shorten a column for which an index exists on� Also, the NOT EXIST clause can be an option of the CREATE or DROP query. The syntax of the NOT EXIST option in CREATE TABLE query is: CREATE TABLE [IF NOT EXISTS] new_table_name( first_column_definition, second_columndefinition, , some_constraints ) ENGINE=storage_eng;
Another straight forward query for this would be to tell MySQL to IGNORE any issues that comes up during the query.
ALTER IGNORE TABLE `surveytable` ADD COLUMN Survey_Name_Qualtrics VARCHAR(20);
MySQL 8.0 Reference Manual :: 13.1.20 CREATE TABLE , An error occurs if the table exists, if there is no default database, or if the database To create one table from another, add a SELECT statement at the end of the If neither NULL nor NOT NULL is specified, the column is treated as though� How to INSERT If Row Does Not Exist (UPSERT) in MySQL. Using INSERT ON DUPLICATE KEY UPDATE. MySQL provides a number of useful statements when it is necessary to INSERT rows after determining whether that row is, in fact, new or already exists.
The answer by diagnonalbatman did not work for me; MySQL 5.7 would complain about syntax errors when I tried it. It probably worked fine with an earlier version of MySQL, but the comment is more than 8 years old after all.
After some trial and error, this is what I ended up with:
DELIMITER // DROP PROCEDURE IF EXISTS addColumn // CREATE PROCEDURE addColumn() BEGIN IF NOT EXISTS ( SELECT * FROM information_schema.COLUMNS WHERE COLUMN_NAME = 'column_name' AND TABLE_NAME = 'table_name' AND TABLE_SCHEMA = DATABASE() ) THEN ALTER TABLE `table_name` ADD COLUMN `column_name` bigint(20) UNSIGNED NOT NULL DEFAULT 1; END IF; END // DELIMITER ; CALL addColumn; DROP PROCEDURE addColumn;
MySQL 8.0 Reference Manual :: 188.8.131.52 CREATE , You can create one table from another by adding a SELECT statement at the end of the MySQL creates new columns for all elements in the SELECT . If neither IGNORE nor REPLACE is specified, duplicate unique key values result in an error. SELECT , if IF NOT EXISTS is given and the target table exists, nothing is � I try to alter and add a new column. I fail. How to repeat: mysql> create table t (s1 int, s2 int) partition by list (s1) -> subpartition by hash (s2) (partition p1 values in (1)); Query OK, 0 rows affected (0.09 sec) mysql> alter table t add column s3 int; ERROR 1499 (HY000): Too many partitions (including subpartitions) were defined
MySQL: How to create Column if not exists?, MySQL ALTER TABLE does not have IF EXISTS specification. You can do the following through using a stored proc or a programming language if this is� Thanks. other solution, do your query in all case and check for the return error (if any). mysql> alter table board add message varchar (255) not null default ''; ERROR 1060 (42S21): Duplicate column name 'message' So, if you get back that error, the column already exists.
MS SQL Server, How have an existing table and want to check if a column name already exists. If not, insert a new column to that table. To add not null constraint to an existing column in MySQL, we will use the ALTER command. This is a type of validation to restrict the user from entering null values. Let us see an example. Firstly, we will create a table.
MySQL Tutorial - MySQL By Examples for Beginners, CREATE TABLE [IF NOT EXISTS] tableName ( columnName columnType columnAttribute, . Modify a table, e.g., ADD COLUMN and DROP COLUMN ALTER TABLE "southwind" has no table (empty set). mysql> SHOW TABLES; Empty set� MySQL Forums Forum List » Newbie. Advanced Search. New Topic. Select column if exists. Posted by: Mihsah Nahk Date: October 26, 2008 06:27AM Hi I wonder if it is
- Check out This Question
- And This question
- If you are going to copy a answer from another forum, its only right to add a link to it. I would like the same to be done when others link to a SO answer.
- this doesn`t work, it still generates errors. @see here: stackoverflow.com/questions/22172221/…