SQL Commands - essentials

 

SELECT

# Retrieve data from the database

FROM

# Specify the table to select data from

WHERE

# Filter rows based on a condition

AS

# Rename a column or table with an alias

JOIN

# Combine rows from two or more tables

ON

# Specify the condition for a JOIN

AND

# Combine multiple conditions, all must be true

OR

# Combine multiple conditions, at least one must be true

LIMIT

# Restrict the number of rows returned

IN

# Specify multiple values in a WHERE clause

CASE

# Create conditional logic within a SQL statement

IS NULL

# Check for empty or NULL values

ORDER BY #

Sort the result set by one or more columns

GROUP BY #

Group rows that share a property into summary rows

HAVING

# Filter groups based on conditions

INSERT INTO

# Add new records to a table

VALUES #

Specify values to insert into the table

UPDATE

# Modify existing records in a table

SET

# Specify the columns and values to update

DELETE

# Remove records from a table

ALTER

# Modify the structure of a table (e.g., add or drop columns)

DROP

# Delete tables, databases, or indexes

DISTINCT

# Retrieve unique values from a column

TRUNCATE #

Delete all records from a table (but keep the structure)

UNION

# Combine the result sets of two or more SELECT queries