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Clean up README code

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* Fixes syntax highlighting of the output from `SqlLiteral`
* Adds whitespace to improve readability
This commit is contained in:
Jeff Cole 2016-02-28 10:05:00 -07:00
parent 1beac5b003
commit f45b5f9dc8
1 changed files with 66 additions and 26 deletions
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README.md
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@ -56,24 +56,48 @@ users.project(users[:id])
Comparison operators `=`, `!=`, `<`, `>`, `<=`, `>=`, `IN`: Comparison operators `=`, `!=`, `<`, `>`, `<=`, `>=`, `IN`:
```ruby ```ruby
users.where(users[:age].eq(10)).project(Arel.sql('*')) # => SELECT * FROM "users" WHERE "users"."age" = 10 users.where(users[:age].eq(10)).project(Arel.sql('*'))
users.where(users[:age].not_eq(10)).project(Arel.sql('*')) # => SELECT * FROM "users" WHERE "users"."age" != 10 # => SELECT * FROM "users" WHERE "users"."age" = 10
users.where(users[:age].lt(10)).project(Arel.sql('*')) # => SELECT * FROM "users" WHERE "users"."age" < 10
users.where(users[:age].gt(10)).project(Arel.sql('*')) # => SELECT * FROM "users" WHERE "users"."age" > 10 users.where(users[:age].not_eq(10)).project(Arel.sql('*'))
users.where(users[:age].lteq(10)).project(Arel.sql('*')) # => SELECT * FROM "users" WHERE "users"."age" <= 10 # => SELECT * FROM "users" WHERE "users"."age" != 10
users.where(users[:age].gteq(10)).project(Arel.sql('*')) # => SELECT * FROM "users" WHERE "users"."age" >= 10
users.where(users[:age].in([20, 16, 17])).project(Arel.sql('*')) # => SELECT * FROM "users" WHERE "users"."age" IN (20, 16, 17) users.where(users[:age].lt(10)).project(Arel.sql('*'))
# => SELECT * FROM "users" WHERE "users"."age" < 10
users.where(users[:age].gt(10)).project(Arel.sql('*'))
# => SELECT * FROM "users" WHERE "users"."age" > 10
users.where(users[:age].lteq(10)).project(Arel.sql('*'))
# => SELECT * FROM "users" WHERE "users"."age" <= 10
users.where(users[:age].gteq(10)).project(Arel.sql('*'))
# => SELECT * FROM "users" WHERE "users"."age" >= 10
users.where(users[:age].in([20, 16, 17])).project(Arel.sql('*'))
# => SELECT * FROM "users" WHERE "users"."age" IN (20, 16, 17)
``` ```
Bitwise operators `&`, `|`, `^`, `<<`, `>>`: Bitwise operators `&`, `|`, `^`, `<<`, `>>`:
```ruby ```ruby
users.where((users[:bitmap] & 16).gt(0)).project(Arel.sql('*')) # => SELECT * FROM "users" WHERE ("users"."bitmap" & 16) > 0 users.where((users[:bitmap] & 16).gt(0)).project(Arel.sql('*'))
users.where((users[:bitmap] | 16).gt(0)).project(Arel.sql('*')) # => SELECT * FROM "users" WHERE ("users"."bitmap" | 16) > 0 # => SELECT * FROM "users" WHERE ("users"."bitmap" & 16) > 0
users.where((users[:bitmap] ^ 16).gt(0)).project(Arel.sql('*')) # => SELECT * FROM "users" WHERE ("users"."bitmap" ^ 16) > 0
users.where((users[:bitmap] << 1).gt(0)).project(Arel.sql('*')) # => SELECT * FROM "users" WHERE ("users"."bitmap" << 1) > 0 users.where((users[:bitmap] | 16).gt(0)).project(Arel.sql('*'))
users.where((users[:bitmap] >> 1).gt(0)).project(Arel.sql('*')) # => SELECT * FROM "users" WHERE ("users"."bitmap" >> 1) > 0 # => SELECT * FROM "users" WHERE ("users"."bitmap" | 16) > 0
users.where((~ users[:bitmap]).gt(0)).project(Arel.sql('*')) # => SELECT FROM "users" WHERE ~ "users"."bitmap" > 0
users.where((users[:bitmap] ^ 16).gt(0)).project(Arel.sql('*'))
# => SELECT * FROM "users" WHERE ("users"."bitmap" ^ 16) > 0
users.where((users[:bitmap] << 1).gt(0)).project(Arel.sql('*'))
# => SELECT * FROM "users" WHERE ("users"."bitmap" << 1) > 0
users.where((users[:bitmap] >> 1).gt(0)).project(Arel.sql('*'))
# => SELECT * FROM "users" WHERE ("users"."bitmap" >> 1) > 0
users.where((~ users[:bitmap]).gt(0)).project(Arel.sql('*'))
# => SELECT FROM "users" WHERE ~ "users"."bitmap" > 0
``` ```
Joins resemble SQL strongly: Joins resemble SQL strongly:
@ -130,18 +154,30 @@ The `AND` operator behaves similarly.
Aggregate functions `AVG`, `SUM`, `COUNT`, `MIN`, `MAX`, `HAVING`: Aggregate functions `AVG`, `SUM`, `COUNT`, `MIN`, `MAX`, `HAVING`:
```ruby ```ruby
photos.group(photos[:user_id]).having(photos[:id].count.gt(5)) # => SELECT FROM photos GROUP BY photos.user_id HAVING COUNT(photos.id) > 5 photos.group(photos[:user_id]).having(photos[:id].count.gt(5))
users.project(users[:age].sum) # => SELECT SUM(users.age) FROM users # => SELECT FROM photos GROUP BY photos.user_id HAVING COUNT(photos.id) > 5
users.project(users[:age].average) # => SELECT AVG(users.age) FROM users
users.project(users[:age].maximum) # => SELECT MAX(users.age) FROM users users.project(users[:age].sum)
users.project(users[:age].minimum) # => SELECT MIN(users.age) FROM users # => SELECT SUM(users.age) FROM users
users.project(users[:age].count) # => SELECT COUNT(users.age) FROM users
users.project(users[:age].average)
# => SELECT AVG(users.age) FROM users
users.project(users[:age].maximum)
# => SELECT MAX(users.age) FROM users
users.project(users[:age].minimum)
# => SELECT MIN(users.age) FROM users
users.project(users[:age].count)
# => SELECT COUNT(users.age) FROM users
``` ```
Aliasing Aggregate Functions: Aliasing Aggregate Functions:
```ruby ```ruby
users.project(users[:age].average.as("mean_age")) # => SELECT AVG(users.age) AS mean_age FROM users users.project(users[:age].average.as("mean_age"))
# => SELECT AVG(users.age) AS mean_age FROM users
``` ```
### The Crazy Features ### The Crazy Features
@ -190,7 +226,8 @@ Joining a table to itself requires aliasing in SQL. This aliasing can be handled
replies = comments.alias replies = comments.alias
comments_with_replies = \ comments_with_replies = \
comments.join(replies).on(replies[:parent_id].eq(comments[:id])).where(comments[:id].eq(1)) comments.join(replies).on(replies[:parent_id].eq(comments[:id])).where(comments[:id].eq(1))
# => SELECT * FROM comments INNER JOIN comments AS comments_2 WHERE comments_2.parent_id = comments.id AND comments.id = 1 # => SELECT * FROM comments INNER JOIN comments AS comments_2
# WHERE comments_2.parent_id = comments.id AND comments.id = 1
``` ```
This will return the reply for the first comment. This will return the reply for the first comment.
@ -212,7 +249,9 @@ users.
project(users[:id], cte_table[:click].sum). project(users[:id], cte_table[:click].sum).
with(composed_cte) with(composed_cte)
# => 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 # => 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
``` ```
When your query is too complex for `Arel`, you can use `Arel::SqlLiteral`: When your query is too complex for `Arel`, you can use `Arel::SqlLiteral`:
@ -225,12 +264,13 @@ photo_clicks = Arel::Nodes::SqlLiteral.new(<<-SQL
ELSE default_calculation END ELSE default_calculation END
SQL SQL
) )
photos.project(photo_clicks.as("photo_clicks")) photos.project(photo_clicks.as("photo_clicks"))
# => SELECT CASE WHEN condition1 THEN calculation1 # => SELECT CASE WHEN condition1 THEN calculation1
WHEN condition2 THEN calculation2 # WHEN condition2 THEN calculation2
WHEN condition3 THEN calculation3 # WHEN condition3 THEN calculation3
ELSE default_calculation END # ELSE default_calculation END
FROM "photos" # FROM "photos"
``` ```
## Contributing to Arel ## Contributing to Arel