.drop column command

  • Article

Applies to: ✅ Azure Data Explorer

Removes a column from a table.

To drop multiple columns from a table, see drop multiple table columns.

Note

This command does not physically delete the data, and does not reduce the cost of storage for data that was already ingested.

Warning

This command is irreversible. All data in the column that is removed will no longer by queryable. Future commands to add that column back will not be able to restore the data.

Permissions

You must have at least Table Admin permissions to run this command.

Syntax

.drop column TableName.ColumnName [ifexists]

Learn more about syntax conventions.

Parameters

Name Type Required Description
TableName string ✔️ The name of the table containing the column to drop.
ColumnName string ✔️ The name of the column to drop.
ifexists string If specified, the command won't fail on a non-existent column.

Example

The following command will drop the Value column from the Test table, if such a column exists. If the column doesn't exist, the command will not fail.

.drop column Test.Value ifexists

Drop multiple table columns

Removes multiple columns from a table.

Note

This command does not physically delete the data, and does not reduce the cost of storage for data that was already ingested.

Warning

This command is irreversible. All data in the column that is removed will no longer by queryable. Future commands to add those columns back will not be able to restore the data.

Syntax

.drop table TableName columns ( ColumnName [, ...] )

Learn more about syntax conventions.

Parameters

Name Type Required Description
TableName string ✔️ The name of the table containing the column to drop.
ColumnName string ✔️ The name of the column to drop.

Example

The following command will drop the Value and Item columns from the Test table.

.drop table Test columns ( Value, Item )