Original subtitles

0 In the last video we learnt how to update rows in a table 1

now let us see how to delete one or more rows from a Table 2

To delete rows, delete query is used. The syntax of delete query is 3

Delete from 4

Mention the table name 5

and then give the condition 6

for the rows to be deleted 7

Condition will be given again using the 8

Where clause 9

Let us see some example 10

If you want to delete a single row 11

We can just run a query 12

to delete from customer table 13

Where customer ID is 14

six 15

If you want to delete multiple rows 16

Say 17

If you want to delete all the customers who are less than 25 years old 18

We will write delete from customers 19

From customer table where 20

Age is less than 25 21

If you want to delete all the rows of the table 22

we will use 23

Delete 24

From customer table and not mention any condition 25

Let's go to PG admin and write these 3 queries 26

Now let us delete the customer with Customer Id 6 27

We'll write delete from 28

Customer table 29

Where 30

Cust ID 31

Is equal to 6 32

Let us run this 33

And let us see the result 34

If you remember earlier we had 10 records after deleting this one record 35

We'll be having 36

9 records 37

We have 8 records in the result because 2 customers had customer ID 38

Six 39

Now 40

If you want to delete, all the customers 41

Whose age is more than 30 years 42

So if we look at the data 43

Customer with customer ID 1 44

And customer ID 45

8 46

Customer ID 4 47

These three customers have 48

age more than 30 years. Let us delete these three customers from our database 49

Delete from customer table 50

Where age 51

is equal to 52

age greater than 30. Let's run this. 53

It ran successfully 54

Let us run the 55

Select query 56

You can see only 57

5 remain 58

earlier we had 8. 3 customers had age more than 30. Now no customer has age more than 30 59

You can delete all the rows of this table 60

To do that 61

we will not specify any condition we will just 62

Tell it to delete 63

From customer table and that's it 64

If we run this query everything from the table will be deleted 65

Let us run this select command 66

You can see only column names are there 67

That's all 68

what this table now has, it has no rows 69

No data in it 70

So that's how you delete data from a Table 71

In the next lecture 72

We will learn, how to change 73

The 74

Structure of the table 75

Structure of the table is comprised of the columns column names or the constraints 76

added to the columns, all these constitute the structure of the table and we will learn how to change the structure of the table