How to Compare Two Queries in SQL
Last Updated :
08 Jun, 2021
Queries in SQL :
A query will either be an invitation for data results from your info or for action on the info, or each. a question will provide you with a solution to a straightforward question, perform calculations, mix data from totally different tables, add, change, or delete data from info.
Creating a Database :
We use CREATE DATABASE command to create a new SQL database.
Syntax –
CREATE DATABASE db_name;
Creating a Table into a created Database :
We use the CREATE TABLE command to create a new SQL database.
Syntax –
CREATE TABLE table_name (
col1 datatype,
col2 datatype,
col3 datatype,
);
Inserting the values into created Table :
We use INSERT INTO command to create a new SQL database.
Syntax –
INSERT INTO table_name
VALUES (value1, value2, value3);
Example Code to create a database and a table into it –
PHP
CREATE DATABASE myDatabase;
CREATE TABLE myTable
(
Pid int,
FName varchar(255),
LName varchar(255),
Adrs varchar(255),
District varchar(255)
);
INSERT INTO myTable (Pid, FName, LName, Adrs, District)
VALUES ( '1' , 'Krishna' , 'Kripa' , 'Jansa' , 'Varanasi' );
|
Output –
myDatabase: myTable
|
Pid
|
FName
|
LName
|
Adrs
|
District
|
1
|
Krishna
|
Kripa
|
Jansa
|
Varanasi
|
Comparison of Queries :
For example, we’ve 2 similar tables in completely different databases and we wish to understand what’s different. Here are the scripts that make sample databases, tables, and information.
PHP
CREATE DATABASE myDatabase1;
GO
USE myDatabase1;
GO
CREATE TABLE myTable
(
Aid int,
Atype varchar(10),
Acost varchar(10)
);
GO
INSERT INTO myTable (Aid, Atype, Acost)
VALUES ( '001' , '1' , '40' ),
( '002' , '2' , '80' ),
( '003' , '3' , '120' )
GO
CREATE DATABASE myDatabase2;
GO
USE myDatabase2;
GO
CREATE TABLE myTable
(
Aid int,
Atype varchar(10),
Acost varchar(10)
);
GO
INSERT INTO myTable (Aid, Atype, Acost)
VALUES ( '001' , '1' , '40' ),
( '002' , '2' , '80' ),
( '003' , '3' , '120' ),
( '004' , '4' , '160' )
GO
|
Output –
For myDatabse1 –
Aid
|
Atype
|
Acost
|
001
|
1
|
40
|
002
|
2
|
80
|
003
|
3
|
120
|
For myDatabase2 –
Aid
|
Atype
|
Acost
|
001
|
1
|
40
|
002
|
2
|
80
|
003
|
3
|
120
|
004
|
4
|
160
|
Compare SQL Queries in Tables by using the EXCEPT keyword :
EXCEPT shows the distinction between 2 tables. it’s wont to compare the variations between 2 tables.
Now run this query where we use the EXCEPT keyword over DB2 from DB1 –
PHP
SELECT * FROM myDatabase2.myTable
EXCEPT
SELECT * FROM myDatabase1.myTable
|
Output –
Aid
|
Atype
|
Acost
|
004
|
4
|
160
|
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