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BASIC POSTGRESQL 0
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Lecture1.1
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Lecture1.2
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Lecture1.3
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Lecture1.4
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Lecture1.5
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Lecture1.6
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VMWARE & POSTGRESQL INSTALLATION 1
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Lecture2.1
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Lecture2.2
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Lecture2.3
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Lecture2.4
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Lecture2.5
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Lecture2.6
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Lecture2.7
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Lecture2.8
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Lecture2.9
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POSTGRESQL DATABASE 0
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Lecture3.1
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Lecture3.2
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Lecture3.3
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Lecture3.4
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Lecture3.5
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Lecture3.6
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POSTGRESQL TABLE 0
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Lecture4.1
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Lecture4.2
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Lecture4.3
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Lecture4.4
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Lecture4.5
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Lecture4.6
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Lecture4.7
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Lecture4.8
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Lecture4.9
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Lecture4.10
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Lecture4.11
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Lecture4.12
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Lecture4.13
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Lecture4.14
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Lecture4.15
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Lecture4.16
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USER/OBJECTS PRIVILEGE AND ROLES ASIGNING 1
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Lecture5.1
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Lecture5.2
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Lecture5.3
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TRANSACTIONS - MVCC 0
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Lecture6.1
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Lecture6.2
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Lecture6.3
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POSTGRESQL USER/SCHEMA MANAGEMENT 1
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Lecture7.1
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Lecture7.2
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Lecture7.3
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Lecture7.4
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Lecture7.5
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Lecture7.6
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Lecture7.7
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Lecture7.8
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Lecture7.9
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POSTGRESQL CONSTRAINTS 0
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Lecture8.1
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Lecture8.2
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Lecture8.3
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Lecture8.4
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Lecture8.5
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Lecture8.6
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POSTGRESQL ADVANCE DATA TYPE 0
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Lecture9.1
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Lecture9.2
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Lecture9.3
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Lecture9.4
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Lecture9.5
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POSTGRESQL VIEWS 0
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Lecture10.1
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POSTGRESQL MONITORING OBJECT USUAGE/SIZE 0
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POSTGRESQL DATABASE ARCHITECTURE 0
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Lecture12.1
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Lecture12.2
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Lecture12.3
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Lecture12.4
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POSTGRESQL BACKUP AND RECOVERY 2
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Lecture13.1
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Lecture13.2
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Lecture13.3
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Lecture13.4
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Lecture13.5
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Lecture13.6
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Lecture13.7
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Lecture13.8
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Lecture13.9
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Lecture13.10
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Lecture13.11
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Lecture13.12
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Lecture13.13
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POSTGRESQL PERFORMANCE TUNING 2
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Lecture14.1
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Lecture14.2
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Lecture14.3
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Lecture14.4
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Lecture14.5
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HIGH AVAILABILITY, LOAD BALANCING, AND REPLICATION 11
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Lecture15.1
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Lecture15.2
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Lecture15.3
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Lecture15.4
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Lecture15.5
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Lecture15.6
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Lecture15.7
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Lecture15.8
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Lecture15.9
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Lecture15.10
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Lecture15.11
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PostgreSQL UNION
PostgreSQL UNION clause/operator is used to combine the results of two or more SELECT statements without returning any duplicate rows
postgres=# select * from tab1; postgres=# select * from tab2;
id | name id | name
----+------- ----+--------
1 | nijam 1 | jamal
2 | abu 2 | smith
3 | umar 4 | daniel
7 | jamal 5 | zaheer
(4 rows) (4 rows)
— From above table tab1 and tab2 having one duplicate values “name=jamal” is duplicate so union clause shows only one rows of tab1 table (7,jamal), table tab2 duplicate row will not show
postgres=# select name from tab1 union select name from tab2;
name
--------
smith
daniel
zaheer
nijam
abu
jamal
umar
(7 rows)
Next
PostgreSQL UNION ALL