SQL ensures data integrity via column’s description

SQL commands cannot retrieve and examine the data stored in a table

ensure that required columns are filled with data and that we do not enter duplicate entries by accident

for inserting rows into table The easiest technique is to import data from a text file or another database.

Text and dates require quotation marks

Numbers, including integers and decimals, require quotation marks

Formatting SQL For readability: SQL keywords, such as SELECT, are capitalized.

Whether the data is clean or dirty, whether it is complete

Data Querying

Selects all columns’ values from the table Using … the wildcard

…. to Find Unique Values

ORDER BY followed by the column or columns to sort.

By default, ORDER BY sorts data in descending order

use the DESC keyword for descending ordering

Each character in a character set is assigned a numeric value

Within a range

Match one of a set of values

Negates a condition

Retrieve all values from ‘state’ column

Every row's state value would be changed to "NE“