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Clean up README code
* Fixes syntax highlighting of the output from `SqlLiteral` * Adds whitespace to improve readability
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Jeff Cole
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1 changed files with 66 additions and 26 deletions
92
README.md
92
README.md
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@ -56,24 +56,48 @@ users.project(users[:id])
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Comparison operators `=`, `!=`, `<`, `>`, `<=`, `>=`, `IN`:
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```ruby
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users.where(users[:age].eq(10)).project(Arel.sql('*')) # => SELECT * FROM "users" WHERE "users"."age" = 10
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users.where(users[:age].not_eq(10)).project(Arel.sql('*')) # => SELECT * FROM "users" WHERE "users"."age" != 10
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users.where(users[:age].lt(10)).project(Arel.sql('*')) # => SELECT * FROM "users" WHERE "users"."age" < 10
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users.where(users[:age].gt(10)).project(Arel.sql('*')) # => SELECT * FROM "users" WHERE "users"."age" > 10
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users.where(users[:age].lteq(10)).project(Arel.sql('*')) # => SELECT * FROM "users" WHERE "users"."age" <= 10
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users.where(users[:age].gteq(10)).project(Arel.sql('*')) # => SELECT * FROM "users" WHERE "users"."age" >= 10
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users.where(users[:age].in([20, 16, 17])).project(Arel.sql('*')) # => SELECT * FROM "users" WHERE "users"."age" IN (20, 16, 17)
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users.where(users[:age].eq(10)).project(Arel.sql('*'))
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# => SELECT * FROM "users" WHERE "users"."age" = 10
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users.where(users[:age].not_eq(10)).project(Arel.sql('*'))
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# => SELECT * FROM "users" WHERE "users"."age" != 10
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users.where(users[:age].lt(10)).project(Arel.sql('*'))
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# => SELECT * FROM "users" WHERE "users"."age" < 10
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users.where(users[:age].gt(10)).project(Arel.sql('*'))
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# => SELECT * FROM "users" WHERE "users"."age" > 10
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users.where(users[:age].lteq(10)).project(Arel.sql('*'))
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# => SELECT * FROM "users" WHERE "users"."age" <= 10
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users.where(users[:age].gteq(10)).project(Arel.sql('*'))
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# => SELECT * FROM "users" WHERE "users"."age" >= 10
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users.where(users[:age].in([20, 16, 17])).project(Arel.sql('*'))
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# => SELECT * FROM "users" WHERE "users"."age" IN (20, 16, 17)
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```
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Bitwise operators `&`, `|`, `^`, `<<`, `>>`:
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```ruby
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users.where((users[:bitmap] & 16).gt(0)).project(Arel.sql('*')) # => SELECT * FROM "users" WHERE ("users"."bitmap" & 16) > 0
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users.where((users[:bitmap] | 16).gt(0)).project(Arel.sql('*')) # => SELECT * FROM "users" WHERE ("users"."bitmap" | 16) > 0
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users.where((users[:bitmap] ^ 16).gt(0)).project(Arel.sql('*')) # => SELECT * FROM "users" WHERE ("users"."bitmap" ^ 16) > 0
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users.where((users[:bitmap] << 1).gt(0)).project(Arel.sql('*')) # => SELECT * FROM "users" WHERE ("users"."bitmap" << 1) > 0
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users.where((users[:bitmap] >> 1).gt(0)).project(Arel.sql('*')) # => SELECT * FROM "users" WHERE ("users"."bitmap" >> 1) > 0
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users.where((~ users[:bitmap]).gt(0)).project(Arel.sql('*')) # => SELECT FROM "users" WHERE ~ "users"."bitmap" > 0
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users.where((users[:bitmap] & 16).gt(0)).project(Arel.sql('*'))
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# => SELECT * FROM "users" WHERE ("users"."bitmap" & 16) > 0
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users.where((users[:bitmap] | 16).gt(0)).project(Arel.sql('*'))
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# => SELECT * FROM "users" WHERE ("users"."bitmap" | 16) > 0
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users.where((users[:bitmap] ^ 16).gt(0)).project(Arel.sql('*'))
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# => SELECT * FROM "users" WHERE ("users"."bitmap" ^ 16) > 0
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users.where((users[:bitmap] << 1).gt(0)).project(Arel.sql('*'))
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# => SELECT * FROM "users" WHERE ("users"."bitmap" << 1) > 0
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users.where((users[:bitmap] >> 1).gt(0)).project(Arel.sql('*'))
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# => SELECT * FROM "users" WHERE ("users"."bitmap" >> 1) > 0
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users.where((~ users[:bitmap]).gt(0)).project(Arel.sql('*'))
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# => SELECT FROM "users" WHERE ~ "users"."bitmap" > 0
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```
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Joins resemble SQL strongly:
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@ -130,18 +154,30 @@ The `AND` operator behaves similarly.
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Aggregate functions `AVG`, `SUM`, `COUNT`, `MIN`, `MAX`, `HAVING`:
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```ruby
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photos.group(photos[:user_id]).having(photos[:id].count.gt(5)) # => SELECT FROM photos GROUP BY photos.user_id HAVING COUNT(photos.id) > 5
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users.project(users[:age].sum) # => SELECT SUM(users.age) FROM users
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users.project(users[:age].average) # => SELECT AVG(users.age) FROM users
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users.project(users[:age].maximum) # => SELECT MAX(users.age) FROM users
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users.project(users[:age].minimum) # => SELECT MIN(users.age) FROM users
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users.project(users[:age].count) # => SELECT COUNT(users.age) FROM users
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photos.group(photos[:user_id]).having(photos[:id].count.gt(5))
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# => SELECT FROM photos GROUP BY photos.user_id HAVING COUNT(photos.id) > 5
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users.project(users[:age].sum)
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# => SELECT SUM(users.age) FROM users
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users.project(users[:age].average)
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# => SELECT AVG(users.age) FROM users
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users.project(users[:age].maximum)
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# => SELECT MAX(users.age) FROM users
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users.project(users[:age].minimum)
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# => SELECT MIN(users.age) FROM users
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users.project(users[:age].count)
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# => SELECT COUNT(users.age) FROM users
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```
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Aliasing Aggregate Functions:
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```ruby
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users.project(users[:age].average.as("mean_age")) # => SELECT AVG(users.age) AS mean_age FROM users
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users.project(users[:age].average.as("mean_age"))
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# => SELECT AVG(users.age) AS mean_age FROM users
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```
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### The Crazy Features
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@ -190,7 +226,8 @@ Joining a table to itself requires aliasing in SQL. This aliasing can be handled
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replies = comments.alias
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comments_with_replies = \
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comments.join(replies).on(replies[:parent_id].eq(comments[:id])).where(comments[:id].eq(1))
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# => SELECT * FROM comments INNER JOIN comments AS comments_2 WHERE comments_2.parent_id = comments.id AND comments.id = 1
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# => SELECT * FROM comments INNER JOIN comments AS comments_2
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# WHERE comments_2.parent_id = comments.id AND comments.id = 1
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```
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This will return the reply for the first comment.
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@ -212,7 +249,9 @@ users.
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project(users[:id], cte_table[:click].sum).
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with(composed_cte)
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# => WITH cte_table AS (SELECT FROM photos WHERE photos.created_at > '2014-05-02') SELECT users.id, SUM(cte_table.click) FROM users INNER JOIN cte_table ON users.id = cte_table.user_id
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# => WITH cte_table AS (SELECT FROM photos WHERE photos.created_at > '2014-05-02')
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# SELECT users.id, SUM(cte_table.click)
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# FROM users INNER JOIN cte_table ON users.id = cte_table.user_id
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```
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When your query is too complex for `Arel`, you can use `Arel::SqlLiteral`:
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@ -225,12 +264,13 @@ photo_clicks = Arel::Nodes::SqlLiteral.new(<<-SQL
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ELSE default_calculation END
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SQL
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)
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photos.project(photo_clicks.as("photo_clicks"))
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# => SELECT CASE WHEN condition1 THEN calculation1
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WHEN condition2 THEN calculation2
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WHEN condition3 THEN calculation3
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ELSE default_calculation END
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FROM "photos"
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# WHEN condition2 THEN calculation2
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# WHEN condition3 THEN calculation3
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# ELSE default_calculation END
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# FROM "photos"
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```
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## Contributing to Arel
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