Chapter 2 - SELECT Statement.md

Chapter 2 - The SELECT Statement

SELECT = 3-Resources/Tools/Developer Tools/Data Stack/Procedural Languages/SQL Code to retrieve data from database

Contents

• Use Cases
• Syntax
• [[#LIMIT|LIMIT]]
• [[#ORDER BY|ORDER BY]]
• Inline Calculations
• Appendix: Links and References

Use Cases

• View data from set of columns in a table
• Combine data from multiple tables
• Filter results from above, perform custom calculations, etc.

Syntax

SELECT [DISTINCT]
	[COLUMN],
	...
FROM
	[SCHEMA].[TABLENAME]
WHERE
	[CONDITIONAL STATEMENTS]
GROUP BY
	[GROUPING FIELDS]
HAVING
	[CONDITIONAL FILTER STATEMENTS AFTER GROUPING]
ORDER BY
	[COLUMNS TO SORT];

Select All:

SELECT * FROM [SCHEMA].[TABLENAME];

LIMIT

• Sets maximum number of rows to return
• Is always the last line of the query

SELECT *
FROM [SCHEMA].[TABLENAME]
LIMIT 5

ORDER BY

• Sort output rows
• Add ASC or DESC
  • In MySQL, NULL values appear first w/ ASC

SELECT * 
FROM [SCHEMA].[TABLENAME] 
ORDER BY [ORDERCOLUMN] DESC
LIMIT 5

Inline Calculations

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Appendix: Links and References

• 2022-10-28
• SQL for Data Scientists
• 3-Resources/Tools/Developer Tools/Data Stack/Procedural Languages/SQL
• Databases

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Jimmy Briggs [email protected] | 2022