Assume you have the table named "t1" with columns names "a", "b", and "c" and you want to delete column "c" from the table.
The below steps will illustrate how to do this:
CREATE TEMPORARY TABLE t1_backup(a,b);
INSERT INTO t1_backup SELECT a,b FROM t1;
DROP TABLE t1;
CREATE TABLE t1(a,b);
INSERT INTO t1 SELECT a,b FROM t1_backup;
DROP TABLE t1_backup;
For adding or deleting columns from an existing table in SQLite:
SQLite has limited ALTER TABLE support that can be used to add a column to the end of the table or to change the name of a table. But, if you wish to make more complex changes in the structure of the table, then you should recreate the table. Try saving the existing data to the temporary table, drop the old table, create the new table, then copy the data back in from the temporary table.
For more information, you can refer to https://www.sqlite.org/faq.html
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