SQL statement to remove duplicate records and obtain duplicate record example code

SQL statement to remove duplicate records and obtain duplicate records
--QueryEffectively remove duplicate records in a table, UserID is an auto-increasing primary key, and RoleID is a repeated field

SELECT MIN(UserID) AS UserID, RoleID FROM tmpTable GROUP BY RoleID 

SELECT RoleID FROM tmpTable GROUP BY RoleID HAVING (COUNT(*) > 1) 

SELECT DISTINCT * FROM tmpTable

sql statement query all table names and field names in the sql server access database February 01, 2007 Thursday 04:21 PMSQL SERVER
View all table names:

select   name   from   sysobjects   where   type='U'

Query table All field names:

Select name from syscolumns Where ID=OBJECT_ID('表名') 

select * from information_schema.tables 
select * from information_schema.views 
select * from information_schema.columns

ACCESS
View all table names:

select   name   from   MSysObjects   where   type=1   and   flags=0

MSysObjects are system objects, which are hidden by default . It can be displayed through tools, options, view, display, and system objects

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