For example,
Table1 have A, B, C three columns
Suppose that there are data
A B C
A001 B001 C001
A002 B002 C001
A003 B003 C001

Table2 have A, B, C, D, E,

Suppose that there are data

A B C D E
A001 B001 C001... .
A002 B002 C001... .
A004 B004 C001... .


Question: I want to find out two C column in the table='C001' A, B two columns of data, data duplication,

CodePudding user response:

The query results, shown in the form of what?

CodePudding user response:

Select a, b from table1 where c='C001' union
Select a, b from table2 where c='C001'


Is to ask the difference between Union and Union all?

CodePudding user response:

Method one:
Select A, B from table1 where C='C001'
The union
Select A, B from table2 where C='C001'

Method 2:
Select
Distinct - remove duplicates
*
The from (
Select A, B from table1 where C='C001'
Union all
Select A, B from table2 where C='C001')

CodePudding user response:

Positive solution, upstairs floor pig is doing?