accept(Token.EXISTS); item.setIfExists(true); } SQLNamename=exprParser.name(); name.setParent(item); item.addColumn(name); Expand Down 5 changes: 5 additions & 0 deletions5core/src/main/java/com/alibaba/druid/sql/dialect/oracle/parser/OracleStatementParser.java ...
下面是一个完整的代码示例,演示了如何使用“如果存在则删除”方法来删除表字段: -- 创建一个示例表CREATETABLEstudents(idINTPRIMARYKEY,nameVARCHAR(50),ageINT);-- 判断字段是否存在,并删除字段ALTERTABLEstudentsDROPCOLUMNIFEXISTSage;-- 输出表结构DESCRIBEstudents; 1. 2. 3. 4. 5. 6. 7. 8. 9. 10....
DROP COLUMN IF EXISTS DROP test, test1, test2; Subject Written By Posted Drop Columns IF EXISTS Jon Rios August 08, 2017 07:02AM Re: Drop Columns IF EXISTS Peter Brawley August 08, 2017 08:08AM Sorry, you can't reply to this topic. It has been closed. ...
CREATE OR REPLACE PROCEDURE DROPEXITSTABS (TAB_NAME_IN IN varchar2) IS v_cnt Number; ...
But if you insist, it's not difficult to simply check for existence first in the client, or to catch the error. MariaDB also supports the following starting with 10.0.2: DROP [COLUMN] [IF EXISTS] col_name i. e. ALTER TABLE my_table DROP IF EXISTS my_column; But it's arguably...
name 能够用于DROP的object_type，如Tables, Database, Function, Trigger, Stored Procedure, Column, User, Type, View, Schema，皆可套用,比如：ALTER TABLE PERSONDROP COLUMN If EXISTS NAME SQL Server 2016新特性：DROP IF EXISTS 标签：basesysges.netschfunctionnameexists删除 ...
DROP COLUMN example_table.column_name; ``` 执行此语句后,名为`example_table`的表中将不再包含被删除的列。 六、注意事项和实战案例 1.在执行DROP语句前,请确保确实需要删除指定的数据库、表或表项,以免误操作造成数据丢失。 2.如果在删除表或数据库时遇到错误,可以使用`ROLLBACK`语句回滚操作,或使用`DROP...
回答：选择database 点击Generation Database 选中Options tab 点击左边table & column或者直接在右边查找 去掉Drop table前面的对号
DROP IF EXISTS的语法如下: DROPobject_typeIFEXISTSobject_name 能够用于DROP的object_type,如Tables, Database, Function, Trigger, Stored Procedure, Column, User, Type, View, Schema,皆可套用,比如: ALTER TABLE PERSON DROP COLUMN If EXISTS NAME...
Unfortunately there is an IF EXISTS clause for CREATE TABLE in MySQL but no one for ALTER TABLE ADD/DROP COLUMN. DROP TABLE IF EXISTS ; CREATE TABLE Solution : Creating following temporary stored procedure would resolve the problem in MySQL 5+: delimiter//CREATE...