To add a column using SQL in Oracle, SQL Server, MySQL, and PostgreSQL, you can use the syntax shown here: ALTERTABLEtable_nameADD[COLUMN]column_name data_type[constraint]; All of these four databases (Oracle, SQL Server, MySQL, and PostgreSQL) use the same SQL add column syntax. So h...
{ ADD COLUMN <列名> <类型>-- 增加列ALTER TABLE 职员 ADD 年末奖金 Money NULL(为职员表添加列,列名为年末奖金,允许为空值,数据类型为货币数据类型。) | CHANGE [COLUMN] <旧列名> <新列名> <新列类型>-- 修改列名或类型 | ALTER [COLUMN] <列名> { SET DEFAULT <默认值> | DROP DEFAULT }-- ...
ALTER TABLE - ADD Column To add a column in a table, use the following syntax: ALTERTABLEtable_name ADDcolumn_name datatype; The following SQL adds an "Email" column to the "Customers" table: ExampleGet your own SQL Server ALTERTABLECustomers ...
INSERT INTO:用于向数据库表中插入新数据。 INSERT INTO table_name(column1,column2,...)VALUES(value1,value2,...) table_name: 要插入数据的表。 column1, column2, ...: 要插入数据的列。 value1, value2, ...: 对应列的值。 UPDATE:用于更新数据库表中的现有数据。 UPDATE table_name SET colu...
ALTER TABLE table_name { ADD COLUMN clause | ALTER COLUMN clause | DROP COLUMN clause | RENAME COLUMN clause } ADD COLUMN 子句 JDBC 数据源不支持此子句。 向表添加一列或多列,或将字段添加到 Delta Lake 表中的现有列。 备注 向现有 Delta 表添加列时,无法定义 DEFAULT 值。 对于...
No additional syntax is required to implement the online operation beyond the ADD COLUMN syntax. A runtime constant is an expression that produces the same value at runtime for each row in the table despite its determinism. For example, the constant expression "My temporary data", or the ...
SQL_AD_ADD_CONSTRAINT_INITIALLY_IMMEDIATE(全级别) SQL_ALTER_TABLE 2.0 一个SQLUINTEGER 位掩码,用于枚举数据源支持的 ALTER TABLE 语句中的子句。必须支持此功能的 SQL-92 或 FIPS 一致性级别显示在每个位掩码旁边的括号中。以下位掩码用于确定支持哪些子句:SQL_AT_ADD_COLUMN_COLLATION = <支持添加列> 子句,...
alteration ::= ADD [COLUMN] column-def The RENAME TO syntax is used to rename the table identified by [database-name.] table-name to new-table-name. This command cannot be used to move a table between attached databases, only to rename a table within the same database. ...
ALTERTABLEtable_nameADDcolumn_name datatype --例如该员工表添加一列员工邮箱: altertablePeopleaddPeopleMail nvarchar(100) (2)如需在表中删除列,请使用下面的语法: ALTERTABLEtable_name DROPCOLUMNcolumn_name --例如删除员工表中的邮箱这一列 altertablePeople ...
constraints for syntax and description of these constraints, as well as examplesinline_constraintUse the inline_constraint to define an integrity constraint as part of the column definition.You can create UNIQUE, PRIMARY KEY, and REFERENCES constraints on scalar attributes of object type columns. You...