SQL Server Cheat Sheet - Pedagogy Zone

An SQL Server Cheat Sheet is a quick reference guide or document that provides concise and handy information about SQL Server commands, syntax, and commonly used queries. It’s a helpful resource for database administrators, developers, or anyone working with SQL Server databases who wants to quickly look up commands or refresh their memory on how to perform specific tasks. The cheat sheet typically includes essential SQL Server commands for tasks like querying data, updating records, creating tables, and managing database permissions. It’s a great tool for efficiency and accuracy when working with SQL Server databases.

SELECT Query

SELECT col1, col2 FROM table JOIN table2 ON table1.col = table2.col WHERE condition GROUP BY column_name HAVING condition ORDER BY col1 ASC|DESC;

SELECT Keywords

DISTINCT: Removes duplicate results	`SELECT DISTINCT product_name FROM product;`
BETWEEN: Matches a value between two other values (inclusive)	`SELECT product_name FROM product WHERE price BETWEEN 50 AND 100;`
IN: Matches to any of the values in a list	`SELECT product_name FROM product WHERE category IN ('Electronics', 'Furniture');`
LIKE: Performs wildcard matches using _ or %	`SELECT product_name FROM product WHERE product_name LIKE '%Desk%";`

Joins

SELECT t1.*, t2.* FROM t1 join_type t2 ON t1.col = t2.col;

INNER JOIN: show all matching records in both tables.
LEFT JOIN: show all records from left table, and any matching records from right table.
RIGHT JOIN: show all records from right table, and any matching records from left table.
FULL JOIN: show all records from both tables, whether there is a match or not.

CASE Statement

Simple Case

CASE name WHEN 'John' THEN 'Name John' WHEN 'Steve' THEN 'Name Steve' ELSE 'Unknown' END

Searched Case

CASE WHEN name='John' THEN 'Name John' WHEN name='Steve' THEN 'Name Steve' ELSE 'Unknown' END

Common Table Expression

WITH queryname (col1, col2...) AS ( SELECT col1, col2 FROM firsttable) SELECT col1, col2.. FROM queryname...;

Modifying Data

Insert	`INSERT INTO tablename (col1, col2...) VALUES (val1, val2);`
Insert from a Table	`INSERT INTO tablename` `(col1, col2...)` `SELECT col1, col2...`
Insert Multiple Rows	`INSERT INTO tablename` `(col1, col2...) VALUES` `(valA1, valB1),` `(valA2, valB2),` `(valA3, valB3);`
Update	`UPDATE tablename SET col1 = val1 WHERE condition;`
Update with a Join	`UPDATE t SET col1 = val1 FROM tablename t INNER JOIN table x ON t.id = x.tid WHERE condition;`
Delete	`DELETE FROM tablename WHERE condition;`

Indexes

Create Index	`CREATE INDEX indexname ON tablename (cols);`
Drop Index	`DROP INDEX indexname;`

Set Operators

UNION: Shows unique rows from two result sets.
UNION ALL: Shows all rows from two result sets.
INTERSECT: Shows rows that exist in both result sets.
MINUS: Shows rows that exist in the first result set but not the second.

Aggregate Functions

SUM: Finds a total of the numbers provided
COUNT: Finds the number of records
AVG: Finds the average of the numbers provided
MIN: Finds the lowest of the numbers provided
MAX: Finds the highest of the numbers provided

Common Functions

LEN(string): Returns the length of the provided string
CHARINDEX(string, substring, [start_position], [occurrence]):
Returns the position of the substring within the specified string.
CAST(expression AS type [(length)]): Converts an expression to
another data type.
GETDATE: Returns the current date, including time.
CEILING(input_val): Returns the smallest integer greater than the
provided number.
FLOOR(input_val): Returns the largest integer less than the
provided number.
ROUND(input_val, round_to, operation): Rounds a number to a
specified number of decimal places.
REPLACE(whole_string, string_to_replace, replacement_string):
Replaces one string inside the whole string with another string.
SUBSTRING(string, start_position, [length]): Returns part of a
value, based on a position and length.

Create Table

Create Table CREATE TABLE tablename ( column_name data_type );

Create Table with Constraints

CREATE TABLE tablename ( column_name data_type NOT NULL, CONSTRAINT pkname PRIMARY KEY (col), CONSTRAINT fkname FOREIGN KEY (col) REFERENCES other_table(col_in_other_table), CONSTRAINT ucname UNIQUE (col), CONSTRAINT ckname CHECK (conditions) );

Create Temporary Table	`SELECT cols INTO #tablename FROM table;`
Drop Table	`DROP TABLE tablename;`

Alter Table

Add Column	`ALTER TABLE tablename ADD columnname datatype;`
Drop Column	`ALTER TABLE tablename DROP COLUMN columnname;`
Modify Column	`ALTER TABLE tablename ALTER COLUMN columnname newdatatype;`
Rename Column	`sp_rename 'table_name.old_column_name', 'new_column_name', 'COLUMN';`
Add Constraint	`ALTER TABLE tablename ADD CONSTRAINT constraintname constrainttype (columns);`
Drop Constraint	`ALTER TABLE tablename DROP CONSTRAINT constraintname;`
Rename Table	`ALTER TABLE tablename RENAME TO newtablename;`

Window/Analytic Functions

function_name ( arguments ) OVER ( [query_partition_clause] [ORDER BY order_by_clause [windowing_clause] ] )

Example using RANK, showing the student details and their rank according to the fees_paid, grouped by gender:

SELECT student_id, first_name, last_name, gender, fees_paid, RANK() OVER ( PARTITION BY gender ORDER BY fees_paid ) AS rank_val FROM student;

Subqueries

Single Row	`SELECT id, last_name, salary FROM employee WHERE salary = ( SELECT MAX(salary) FROM employee );`
Multi Row	`SELECT id, last_name, salary FROM employee WHERE salary IN ( SELECT salary FROM employee WHERE last_name LIKE 'C%' );`