-- attempt to drop column HomePhone using IF EXISTS to see if it exists – SQL Server 2016 and upALTERTABLE[dbo].[Employees]DROPCOLUMNIFEXISTS[HomePhone]GOSELECT*FROM[dbo].[Employees]GO Now, if we run the same statement to drop the column we know is no longer there the statement will...
TheDROP TABLEstatement is used to drop an existing table in a database. Syntax DROPTABLEtable_name; Note:Be careful before dropping a table. Deleting a table will result in loss of complete information stored in the table! SQL DROP TABLE Example ...
ALTERTABLE[IFEXISTS]table_name {ADD{<schema_component>|(<schema_component>[,...])}|MODIFY{<schema_component>|(<schema_component>[,...])}|DROP{column_name|(column_name,column_name,...)|PRIMARYKEY|CONSTRAINTconstraint_name|WATERMARK}|RENAMEold_column_nameTOnew_column_name|RENAMETOnew_table_...
Here, the SQL command will delete a table namedShippings. Also, make sure you haveadminorDROPpermission to run this command. DROP TABLE Syntax The syntax of the SQLDROP TABLEstatement is: DROPTABLEtable_name; Here,table_nameis the name of the table to be removed. Note:When we delete a ...
335 336 ALTER COLUMN 可以为一列指定一个新的缺省值或删除老的缺省值。如果老的缺省值被移除且列可以被设为 NULL,新的缺省值将是 NULL。如果该列不允许有 NULL值,MySQL 以章节 6.5.3 CREATE TABLE 句法 中的描述方式为该列赋于一个缺省值。 337 338 DROP INDEX 移除一个索引。这是 MySQL 对 ANSI SQL92...
Syntax of a SQL DELETE StatementDELETE FROM table_name [WHERE condition]; table_name -- the table name which has to be updated.NOTE: The WHERE clause in the sql delete command is optional and it identifies the rows in the column that gets deleted. If you do not include the WHERE ...
The following SQL statement drops the existing database "testDB":ExampleGet your own SQL Server DROP DATABASE testDB; Tip: Make sure you have admin privilege before dropping any database. Once a database is dropped, you can check it in the list of databases with the following SQL command...
In SQL, the DROP DATABASE statement is used to delete databases. In this tutorial, you will learn about the SQL DROP DATABASE statement with the help of examples.
SQL Replication must be at Version 10.2.1 (ARCH_LEVEL 1021) or higher. About this task After you issue an ALTER TABLE DROP COLUMN statement for a source table and then a REORG statement for the table space, the Capture program detects the change, removes the column from ...
public boolean supportsAlterTableWithDropColumn() 返回值 如果支持,则值为 true。 否则为false。 例外 SQLServerException 备注 此supportsAlterTableWithDropColumn 方法是由 java.sql.DatabaseMetaData 接口中的 supportsAlterTableWithDropColumn 方法指定的。