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温州网站建设中常用数据库查询判断表、字段是否存在:
1、MSSQL Server
表:select COUNT(*) from dbo.sysobjects WHERE name= 'table_name';
字段:select COUNT(*) from syscolumns WHERE id=object_id(‘table_name’) and name= 'column_name';
2、My SQL
表:select COUNT(*) from information_schema.tables WHERE table_name = 'table_name';
字段:select COUNT(*) from information_schema.columns WHERE table_name = 'table_name' and column_name = 'column_name';
3、Oracle
表:SELECT count(*) FROM USER_OBJECTS WHERE OBJECT_NAME = 'table_name';
字段:SELECT COUNT(*) FROM USER_TAB_COLUMNS WHERE TABLE_NAME = 'table_name' and column_name = 'column_name';
4、PostgreSql
表:select count(*) from information_schema.tables WHERE table_schema='table_schema' and table_name ='table_name';
字段:select count(*) from information_schema.columns WHERE table_schema='table_schema' and table_name ='table_name' and column_name='column_name';
总结:以上结果为1表示存在,为0表示不存在。