sql - ALTER TABLE WHERE Clause - Stack Overflow
Oct 13, 2014 · This is why there is no WHERE clause for ALTER. It sounds like you are looking to drop this column only if all of the values are NULL in the table. What you need is an IF statement. Updated: WHEN NOT EXISTS (SELECT * FROM my_table WHERE col IS NOT NULL) THEN 'Y' ELSE 'N' ALTER TABLE...
SQL ALTER TABLE Statement - W3Schools
The ALTER TABLE statement is used to add, delete, or modify columns in an existing table. The ALTER TABLE statement is also used to add and drop various constraints on an existing table. ALTER TABLE - ADD Column
SQL UPDATE Statement - W3Schools
Notice the WHERE clause in the UPDATE statement. The WHERE clause specifies which record(s) that should be updated. If you omit the WHERE clause, all records in the table will be updated!
sql - ALTER TABLE using WHERE clause condition - Stack Overflow
Jul 20, 2021 · ALTER TABLE cp_asset_translations CHANGE caption caption VARCHAR(1000) DEFAULT NULL; Note: I assume that this ALTER TABLE is valid in the database you are using. The statement varies significantly across databases.
SQL ALTER TABLE - GeeksforGeeks
Jan 30, 2025 · The ALTER TABLE statement in SQL is used to modify an existing table structure in a database without losing any data. It allows you to add, remove, or modify columns, change data types, or apply constraints to improve data integrity and ensure that the table meets evolving business requirements .
How to Modify Existing Data in SQL? | GeeksforGeeks
Dec 17, 2024 · The ALTER TABLE statement in SQL is a powerful command used to modify the structure of an existing table without affecting its data. It enables changes like adding, dropping, renaming or altering columns in the table.
SQL ALTER TABLE Statement - SQL Tutorial
In SQL, the ALTER TABLE statement changes the structure of an existing table. Here’s the syntax of the ALTER TABLE statement: action; Code language: SQL (Structured Query Language) (sql) In this syntax: First, provide the name of the table you want to change in the ALTER TABLE clause. Second, specify an action you want to perform.
SQL ALTER Command - Online Tutorials Library
Following is the basic syntax of an ALTER TABLE command −. ALTER TABLE table_name [alter_option ...]; Where, the alter_option depends on the type of operation to be performed on a table. This article will discuss such important operations one by one.
SQL ALTER TABLE Statement (With Examples) - Programiz
In SQL, the ALTER TABLE command is used to modify the structure of an existing table like adding, deleting, renaming columns, etc. ADD phone varchar(10); Here, the SQL command adds a column named phone to the Customers table. The …
10 Example of ALTER Clause in SQL - SQLrevisited
Jan 13, 2025 · Here are different ways to use ALTER command in SQL to modify table or stored procure in database. Each example will tell you a particular job like adding or removing new columns, index and more. 1. How to add a new column in SQL Server database. You can use ADD keyword with ALERT command to add a new column in SQL.
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