With this procedure defined, one need only CALL dropMatchingColumns('test\_%') in order to drop all the columns prefixed with test_ from the current database. CREATE TABLE DeleteIDs SELECT id FROM table1 WHERE 12 INSERT INTO table1 SELECT A.id FROM table1 A INNER JOIN table2 b ON A.id B.id AND a.field1 b.field1 AND a.field2 b.field2 AND a.field3 b.field3 AND b.id ALTER TABLE DeleteIDs ADD PRIMARY KEY (id) DELETE B. First, write ALTER TABLE, followed by the name of the table you want to change (in our example, product ). WHERE COLUMN_NAME LIKE pattern AND TABLE_SCHEMA = DATABASE()ĭECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE The DROP COLUMN command is used to delete a column in an existing table. 'DROP COLUMN `', REPLACE(COLUMN_NAME, '`', '``'), '`' The phpMyAdmin tool allows users to DROP a particular column in your table instead of deleting the entire table itself. We will be creating a table studentsdata followed by adding some rows to it. 'ALTER TABLE `', REPLACE( TABLE_NAME, '`', '``'), '` ', 2 I am trying to execute a MySQL query to delete rows from 'table2' where column 'value' IF column in 'table1' 'value' I have 2 tables. MySQL delete column from a table syntax MySQL delete column from a table example MySQL drop a column with foreign key Before moving ahead into the tutorial, let us look at the data we will be using in the examples. Whilst it is possible to do that within a MySQL stored procedure using SQL prepared statements, which I demonstrate below, you may well find it easier to implement/understand in your preferred development language (which you do not mention in your question): DELIMITER ĬREATE PROCEDURE dropMatchingColumns(IN pattern VARCHAR(64))
In SQLite, this function generate drop/create view queries (view columns can. If you actually want to drop the columns from your schema, you will need to generate the necessary SQL commands dynamically from MySQL's information schema tables. Callback function can be specified to add columns in the duplicated table.
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