Sql

Question 1

How do you eliminate duplicates in sql

Answer 1

Select distinct

Question 2

How do you name the column you are returning from database

Answer 2

As

Question 3

How do you select what table you are querying in the database

Answer 3

Select* if searching the entire database
Select from to specify a table

Question 4

String length

Answer 4

Len(column)
Length(column)

Question 5

How do you add conditions

Answer 5

Where

Question 6

How do you use the substring function

Answer 6

Substring(column,position of first character you want to return, total length of the substring)

Question 7

Dml

Answer 7

Data manipulation language

Question 8

Cast()

Answer 8

Can be used to convert anything from one data type to another.

Question 9

Coalesce

Answer 9

Coalesce(columna,columnb) if no value in a it returns value in b

Question 10

How do you change data types?

Answer 10

Cast
Cast as [data type]
From table

Question 11

How do you avoid failed returns when casting (error)

Answer 11

Safe_cast: returns null value where the errors are. This allows the action to be completed without failing the entire command.

Question 12

What data types are ther

Answer 12

Int
String
Datetime
Many more

Question 13

What is unix_date

Answer 13

UNIX_DATE returns the number of days that have passed since January 1, 1970 and is used to compare and work with dates across multiple time zones. You will likely use CAST most often.

Question 14

Concat_ws

Answer 14

With separator adds character between

Question 15

Sql stores info In a 64 bit memory system

Answer 15

Int64

Question 16

Join

Answer 16

Part of a from clause. From table1, join table 2
On table 1. Column name
Signifies how tables are to be matched for the correct information to be combined from both.

Question 17

Types of joins

Answer 17

Right join, left join, inner, full outer

Question 18

Types of joins

Answer 18

Right join, left join, inner, full outer

Question 19

Inner join

Answer 19

Combines only info in both the tables

Question 20

Outer join

Answer 20

Combines only distinct info from both tables

Question 21

Left join

Answer 21

From
Table1.name
Table2.salesrep
Left join table 1
On customer.customerid = sales.customerid

Question 22

Left join

Answer 22

From
Table1.name
Table2.salesrep
Left join table 1
On customer.customerid = sales.customerid

Question 23

Full outer join

Answer 23

Returns all data from both tables paired up. Even if there are no pairs it will return the value with null

Question 24

Full outer join

Answer 24

Returns all data from both tables paired up. Even if there are no pairs it will return the value with null

Question 25

Foreign key

Answer 25

Links data in one table to data in another table. Same data type as the primary key it references

Question 26

IN operator

Answer 26

The IN operator allows you to specify multiple values in a where clause