Thanksgiving Venn Diagram explains the complete picture.
Sunday, November 30, 2014
Saturday, November 22, 2014
SQL to Hive Cheat Sheet
Retrieving Information
Function | MySQL | Hive |
Retrieving Information (General) | SELECT from_columns FROM table WHERE conditions; | SELECT from_columns FROM table WHERE conditions; |
Retrieving All Values | SELECT * FROM table; | SELECT * FROM table; |
Retrieving Some Values | SELECT * FROM table WHERE rec_name = "value"; | SELECT * FROM table WHERE rec_name = "value"; |
Retrieving With Multiple Criteria | SELECT * FROM TABLE WHERE rec1 = "value1" AND rec2 = "value2"; | SELECT * FROM TABLE WHERE rec1 = "value1" AND rec2 = "value2"; |
Retrieving Specific Columns | SELECT column_name FROM table; | SELECT column_name FROM table; |
Retrieving Unique Output | SELECT DISTINCT column_name FROM table; | SELECT DISTINCT column_name FROM table; |
Sorting | SELECT col1, col2 FROM table ORDER BY col2; | SELECT col1, col2 FROM table ORDER BY col2; |
Sorting Reverse | SELECT col1, col2 FROM table ORDER BY col2 DESC; | SELECT col1, col2 FROM table ORDER BY col2 DESC; |
Counting Rows | SELECT COUNT(*) FROM table; | SELECT COUNT(*) FROM table; |
Grouping With Counting | SELECT owner, COUNT(*) FROM table GROUP BY owner; | SELECT owner, COUNT(*) FROM table GROUP BY owner; |
Maximum Value | SELECT MAX(col_name) AS label FROM table; | SELECT MAX(col_name) AS label FROM table; |
Selecting from multiple tables (Join same table using alias w/”AS”) | SELECT pet.name, comment FROM pet, event WHERE pet.name = event.name; | SELECT pet.name, comment FROM pet JOIN event ON (pet.name = event.name) |
Metadata
Function | MySQL | Hive |
Selecting a database | USE database; | USE database; |
Listing databases | SHOW DATABASES; | SHOW DATABASES; |
Listing tables in a database | SHOW TABLES; | SHOW TABLES; |
Describing the format of a table | DESCRIBE table; | DESCRIBE (FORMATTED|EXTENDED) table; |
Creating a database | CREATE DATABASE db_name; | CREATE DATABASE db_name; |
Dropping a database | DROP DATABASE db_name; | DROP DATABASE db_name (CASCADE); |
Current SQL Compatibility
Command Line
Function | Hive |
Run Query | hive -e 'select a.col from tab1 a' |
Run Query Silent Mode | hive -S -e 'select a.col from tab1 a' |
Set Hive Config Variables | hive -e 'select a.col from tab1 a' -hiveconf hive.root.logger=DEBUG,console |
Use Initialization Script | hive -i initialize.sql |
Run Non-Interactive Script Source | hive -f script.sql |
Sunday, November 9, 2014
Funny: SQL Joke
Q: Why do you never ask SQL developers to help you move your furniture?
A: They sometimes drop tables.
A: They sometimes drop tables.
Funny: How to spot a Burglar
An Oak Hill community couple discovered a thief in their home Saturday after a man told a joke and heard a laugh upstairs :).
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