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常用数据库查询之一(判断表和字段是否存在)

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2016-06-07 15:47:331448浏览

参数table_name和column_name的均为大写: 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:sel

 

参数table_name和column_name的值均为大写:

 

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';

 

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