Reserved words are words that cannot be used as identifiers (such as variable names or function names) in a programming language, because they have a specific meaning in the language itself. Selecting rows that occur in the first SELECT statement but not the second SELECT statement: SELECT * from customer_usaįROM state_ca Important Concepts and Resources: Reserved words Selecting rows that occur in both SELECT statements: SELECT * from customer_usa Selecting rows that occur in one or more SELECT statements: INNER JOIN artist ar ON ar.artist_id = al.artist_idĬreating a view: CREATE VIEW chinook.customer_2 ASĭropping a view: DROP VIEW chinook.customer_2 INNER JOIN album al ON al.album_id = t.album_id Using the WITH clause: WITH track_info AS Using if/then logic in SQL with CASE: CASE JOIN ON Other common SQL operations:Ĭombining columns into a single column: SELECT Joining data from more than two tables: SELECT FROM Using a join within a subquery, with a limit: SELECT c.name capital_city, f.name country ORDER BY 2 desc - 2 refers to migration_rate column Sorting a column without specifying a column name: SELECT name, migration_rate FROM FACTS Joining tables using a FULL OUTER JOIN: SELECT f.name country, c.name cityįULL OUTER JOIN facts f ON f.id = c.facts_id Joining tables using a RIGHT JOIN: SELECT f.name country, c.name city ![]() LEFT JOIN cities ON cities.facts_id = facts.id Joining tables using a LEFT JOIN: SELECT * FROM facts INNER JOIN table_name_2 ON table_name_1.column_name_1 = table_name_2.column_name_1 Joining tables with INNER JOIN: SELECT column_name_1, column_name_2 FROM table_name_1 For more information, sign up for a free account and try one out! Joining data in SQL: Many of these examples use table and column names from the real SQL databases that learners work with in our interactive SQL courses. SELECT column_1, column_2, column_3 - Second commentįROM table_name SQL Intermediate: Joins & Complex Queries LIMIT 10 Adding comments to your SQL queriesĪdding single-line comments: - First comment Select specific columns from a table: SELECT column_name_1, column_name_2ĭisplay the first 10 rows on a table: SELECT * SQL uses the following order of precedence: FROM, SELECT, LIMIT. Remember: The order of clauses matters in SQL. SELECT 2*3 AS mult, 1+2+3 AS nice_sum Selecting tables, columns, and rows: Performing calculations with multiple numbers: SQL Cheat Sheet: Fundamentals Performing calculations with SQL For this reason, today it is sometimes pronounced “Sequel” and sometimes pronounced “S.Q.L.” Either pronunciation is acceptableĪlthough there are many “flavors” of SQL, SQL in some form can be used for querying data from most relational database systems, including MySQL, SQLite, Oracle, Microsoft SQL Server, PostgreSQL, IBM DB2, Microsoft Azure SQL Database, Apache Hive, etc. It is a system for querying - requesting, filtering, and outputting - data from relational databases.ĭeveloped in the 1970s, SQL was originally called SEQUEL. ![]() ![]() SQL stands for Structured Query Language. Need to brush up on your SQL before you’re ready for the cheat sheet? Check out our interactive online SQL Fundamentals course, read about why you should learn SQL, or do some research about SQL certifications and whether you’ll need one. Our SQL cheat sheet goes a bit more in-depth than this handwritten one!
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