Back
limit (clj)
(source)function
(limit limit)
Specific to some databases (notabley MySQL),
accepts a single SQL expression:
(limit 40)
Produces: LIMIT ?
Parameters: 40
The two-argument syntax is not supported: use `offset`
instead:
`LIMIT 20,10` is equivalent to `LIMIT 10 OFFSET 20`
(-> (limit 10) (offset 20))
Examples
honeysql
(ns honey.sql-test
(:refer-clojure :exclude [format])
(:require [clojure.string :as str]
[clojure.test :refer [deftest is testing]]
[honey.sql :as sut :refer [format]]
[honey.sql.helpers :as h])
#?(:clj (:import (clojure.lang ExceptionInfo))))
(deftest inner-parts-test
(testing "The correct way to apply ORDER BY to various parts of a UNION"
(is (= (format
{:union
[{:select [:amount :id :created_on]
:from [:transactions]}
{:select [:amount :id :created_on]
:from [{:select [:amount :id :created_on]
:from [:other_transactions]
:order-by [[:amount :desc]]
:limit 5}]}]
:order-by [[:amount :asc]]})
["SELECT amount, id, created_on FROM transactions UNION SELECT amount, id, created_on FROM (SELECT amount, id, created_on FROM other_transactions ORDER BY amount DESC LIMIT ?) ORDER BY amount ASC" 5]))))
(deftest fetch-offset-issue-338
(testing "default offset (with and without limit)"
(is (= ["SELECT foo FROM bar LIMIT ? OFFSET ?" 10 20]
(format {:select :foo :from :bar
:limit 10 :offset 20})))
(is (= ["SELECT foo FROM bar OFFSET ?" 20]
(format {:select :foo :from :bar
:offset 20}))))
(testing "default offset / fetch"
(is (= ["SELECT foo FROM bar OFFSET ? ROWS FETCH NEXT ? ROWS ONLY" 20 10]
(format {:select :foo :from :bar
:fetch 10 :offset 20})))
(is (= ["SELECT foo FROM bar OFFSET ? ROW FETCH NEXT ? ROW ONLY" 1 1]
(format {:select :foo :from :bar
:fetch 1 :offset 1})))
(is (= ["SELECT foo FROM bar FETCH FIRST ? ROWS ONLY" 2]
(format {:select :foo :from :bar
:fetch 2}))))
(testing "SQL Server offset"
(is (= ["SELECT [foo] FROM [bar] OFFSET ? ROWS FETCH NEXT ? ROWS ONLY" 20 10]
(format {:select :foo :from :bar
:fetch 10 :offset 20}
{:dialect :sqlserver})))
(is (= ["SELECT [foo] FROM [bar] OFFSET ? ROWS" 20]
(format {:select :foo :from :bar
:offset 20}
{:dialect :sqlserver})))))
honeysql
(ns honey.sql.helpers-test
(:refer-clojure :exclude [filter for group-by partition-by set update])
(:require [clojure.test :refer [deftest is testing]]
[honey.sql :as sql]
[honey.sql.helpers :as h
:refer [add-column add-index alter-table columns create-table create-table-as create-view
create-materialized-view drop-view drop-materialized-view
create-index
bulk-collect-into
cross-join do-update-set drop-column drop-index drop-table
filter from full-join
group-by having insert-into
join-by join lateral left-join limit offset on-conflict
on-duplicate-key-update
order-by over partition-by refresh-materialized-view
rename-column rename-table returning right-join
select select-distinct select-top select-distinct-top
values where window with with-columns
with-data within-group]]))
(deftest test-select
(testing "large helper expression"
(let [m1 (-> (with [:cte (-> (select :*)
(from :example)
(where [:= :example-column 0]))])
(select-distinct :f.* :b.baz :c.quux [:b.bla "bla-bla"]
:%now [[:raw "@x := 10"]])
(from [:foo :f] [:baz :b])
(join :draq [:= :f.b :draq.x])
(left-join [:clod :c] [:= :f.a :c.d])
(right-join :bock [:= :bock.z :c.e])
(full-join :beck [:= :beck.x :c.y])
(where [:or
[:and [:= :f.a "bort"] [:not= :b.baz :?param1]]
[:and [:< 1 2] [:< 2 3]]
[:in :f.e [1 [:param :param2] 3]]
[:between :f.e 10 20]])
(group-by :f.a)
(having [:< 0 :f.e])
(order-by [:b.baz :desc] :c.quux [:f.a :nulls-first])
(limit 50)
(offset 10))
m2 {:with [[:cte {:select [:*]
:from [:example]
:where [:= :example-column 0]}]]
:select-distinct [:f.* :b.baz :c.quux [:b.bla "bla-bla"]
:%now [[:raw "@x := 10"]]]
:from [[:foo :f] [:baz :b]]
:join [:draq [:= :f.b :draq.x]]
:left-join [[:clod :c] [:= :f.a :c.d]]
:right-join [:bock [:= :bock.z :c.e]]
:full-join [:beck [:= :beck.x :c.y]]
:where [:or
[:and [:= :f.a "bort"] [:not= :b.baz :?param1]]
[:and [:< 1 2] [:< 2 3]]
[:in :f.e [1 [:param :param2] 3]]
[:between :f.e 10 20]]
:group-by [:f.a]
:having [:< 0 :f.e]
:order-by [[:b.baz :desc] :c.quux [:f.a :nulls-first]]
:limit 50
:offset 10}]
(testing "Various construction methods are consistent"
(is (= m1 m2)))
(testing "SQL data formats correctly"
(is (= ["WITH cte AS (SELECT * FROM example WHERE example_column = ?) SELECT DISTINCT f.*, b.baz, c.quux, b.bla AS \"bla-bla\", NOW(), @x := 10 FROM foo AS f, baz AS b INNER JOIN draq ON f.b = draq.x LEFT JOIN clod AS c ON f.a = c.d RIGHT JOIN bock ON bock.z = c.e FULL JOIN beck ON beck.x = c.y WHERE ((f.a = ?) AND (b.baz <> ?)) OR ((? < ?) AND (? < ?)) OR (f.e IN (?, ?, ?)) OR f.e BETWEEN ? AND ? GROUP BY f.a HAVING ? < f.e ORDER BY b.baz DESC, c.quux ASC, f.a NULLS FIRST LIMIT ? OFFSET ?"
0 "bort" "gabba" 1 2 2 3 1 2 3 10 20 0 50 10]
(sql/format m1 {:params {:param1 "gabba" :param2 2}}))))
#?(:clj (testing "SQL data prints and reads correctly"
(is (= m1 (read-string (pr-str m1))))))
#_(testing "SQL data formats correctly with alternate param naming"
(is (= (sql/format m1 {:params {:param1 "gabba" :param2 2}})
["WITH cte AS (SELECT * FROM example WHERE example_column = $1) SELECT DISTINCT f.*, b.baz, c.quux, b.bla \"bla-bla\", NOW(), @x := 10 FROM foo AS f, baz AS b INNER JOIN draq ON f.b = draq.x LEFT JOIN clod AS c ON f.a = c.d RIGHT JOIN bock ON bock.z = c.e FULL JOIN beck ON beck.x = c.y WHERE ((f.a = $2) AND (b.baz <> $3)) OR (($4 < $5) AND ($6 < $7)) OR (f.e IN ($8, $9, $10)) OR f.e BETWEEN $11 AND $12 GROUP BY f.a HAVING $13 < f.e ORDER BY b.baz DESC, c.quux ASC, f.a NULLS FIRST LIMIT $14 OFFSET $15"
0 "bort" "gabba" 1 2 2 3 1 2 3 10 20 0 50 10])))
(testing "Locking"
(is (= ["WITH cte AS (SELECT * FROM example WHERE example_column = ?) SELECT DISTINCT f.*, b.baz, c.quux, b.bla AS `bla-bla`, NOW(), @x := 10 FROM foo AS f, baz AS b INNER JOIN draq ON f.b = draq.x LEFT JOIN clod AS c ON f.a = c.d RIGHT JOIN bock ON bock.z = c.e FULL JOIN beck ON beck.x = c.y WHERE ((f.a = ?) AND (b.baz <> ?)) OR ((? < ?) AND (? < ?)) OR (f.e IN (?, ?, ?)) OR f.e BETWEEN ? AND ? GROUP BY f.a HAVING ? < f.e ORDER BY b.baz DESC, c.quux ASC, f.a NULLS FIRST LIMIT ? OFFSET ? LOCK IN SHARE MODE"
0 "bort" "gabba" 1 2 2 3 1 2 3 10 20 0 50 10]
(sql/format (assoc m1 :lock [:in-share-mode])
{:params {:param1 "gabba" :param2 2}
;; to enable :lock
:dialect :mysql :quoted false}))))))
(testing "large helper expression with simplified where"
(let [m1 (-> (with [:cte (-> (select :*)
(from :example)
(where := :example-column 0))])
(select-distinct :f.* :b.baz :c.quux [:b.bla "bla-bla"]
:%now [[:raw "@x := 10"]])
(from [:foo :f] [:baz :b])
(join :draq [:= :f.b :draq.x])
(left-join [:clod :c] [:= :f.a :c.d])
(right-join :bock [:= :bock.z :c.e])
(full-join :beck [:= :beck.x :c.y])
(where :or
[:and [:= :f.a "bort"] [:not= :b.baz :?param1]]
[:and [:< 1 2] [:< 2 3]]
[:in :f.e [1 [:param :param2] 3]]
[:between :f.e 10 20])
(group-by :f.a)
(having :< 0 :f.e)
(order-by [:b.baz :desc] :c.quux [:f.a :nulls-first])
(limit 50)
(offset 10))
m2 {:with [[:cte {:select [:*]
:from [:example]
:where [:= :example-column 0]}]]
:select-distinct [:f.* :b.baz :c.quux [:b.bla "bla-bla"]
:%now [[:raw "@x := 10"]]]
:from [[:foo :f] [:baz :b]]
:join [:draq [:= :f.b :draq.x]]
:left-join [[:clod :c] [:= :f.a :c.d]]
:right-join [:bock [:= :bock.z :c.e]]
:full-join [:beck [:= :beck.x :c.y]]
:where [:or
[:and [:= :f.a "bort"] [:not= :b.baz :?param1]]
[:and [:< 1 2] [:< 2 3]]
[:in :f.e [1 [:param :param2] 3]]
[:between :f.e 10 20]]
:group-by [:f.a]
:having [:< 0 :f.e]
:order-by [[:b.baz :desc] :c.quux [:f.a :nulls-first]]
:limit 50
:offset 10}]
(testing "Various construction methods are consistent"
(is (= m1 m2)))
(testing "SQL data formats correctly"
(is (= ["WITH cte AS (SELECT * FROM example WHERE example_column = ?) SELECT DISTINCT f.*, b.baz, c.quux, b.bla AS \"bla-bla\", NOW(), @x := 10 FROM foo AS f, baz AS b INNER JOIN draq ON f.b = draq.x LEFT JOIN clod AS c ON f.a = c.d RIGHT JOIN bock ON bock.z = c.e FULL JOIN beck ON beck.x = c.y WHERE ((f.a = ?) AND (b.baz <> ?)) OR ((? < ?) AND (? < ?)) OR (f.e IN (?, ?, ?)) OR f.e BETWEEN ? AND ? GROUP BY f.a HAVING ? < f.e ORDER BY b.baz DESC, c.quux ASC, f.a NULLS FIRST LIMIT ? OFFSET ?"
0 "bort" "gabba" 1 2 2 3 1 2 3 10 20 0 50 10]
(sql/format m1 {:params {:param1 "gabba" :param2 2}}))))
#?(:clj (testing "SQL data prints and reads correctly"
(is (= m1 (read-string (pr-str m1))))))
#_(testing "SQL data formats correctly with alternate param naming"
(is (= (sql/format m1 {:params {:param1 "gabba" :param2 2}})
["WITH cte AS (SELECT * FROM example WHERE example_column = $1) SELECT DISTINCT f.*, b.baz, c.quux, b.bla \"bla-bla\", NOW(), @x := 10 FROM foo AS f, baz AS b INNER JOIN draq ON f.b = draq.x LEFT JOIN clod AS c ON f.a = c.d RIGHT JOIN bock ON bock.z = c.e FULL JOIN beck ON beck.x = c.y WHERE ((f.a = $2) AND (b.baz <> $3)) OR (($4 < $5) AND ($6 < $7)) OR (f.e IN ($8, $9, $10)) OR f.e BETWEEN $11 AND $12 GROUP BY f.a HAVING $13 < f.e ORDER BY b.baz DESC, c.quux ASC, f.a NULLS FIRST LIMIT $14 OFFSET $15"
0 "bort" "gabba" 1 2 2 3 1 2 3 10 20 0 50 10])))
(testing "Locking"
(is (= ["WITH cte AS (SELECT * FROM example WHERE example_column = ?) SELECT DISTINCT f.*, b.baz, c.quux, b.bla AS `bla-bla`, NOW(), @x := 10 FROM foo AS f, baz AS b INNER JOIN draq ON f.b = draq.x LEFT JOIN clod AS c ON f.a = c.d RIGHT JOIN bock ON bock.z = c.e FULL JOIN beck ON beck.x = c.y WHERE ((f.a = ?) AND (b.baz <> ?)) OR ((? < ?) AND (? < ?)) OR (f.e IN (?, ?, ?)) OR f.e BETWEEN ? AND ? GROUP BY f.a HAVING ? < f.e ORDER BY b.baz DESC, c.quux ASC, f.a NULLS FIRST LIMIT ? OFFSET ? LOCK IN SHARE MODE"
0 "bort" "gabba" 1 2 2 3 1 2 3 10 20 0 50 10]
(sql/format (assoc m1 :lock [:in-share-mode])
{:params {:param1 "gabba" :param2 2}
;; to enable :lock
:dialect :mysql :quoted false})))))))
honeysql
(ns honey.cache-test
(:refer-clojure :exclude [format group-by])
(:require [clojure.core.cache.wrapped :as cache]
[clojure.test :refer [deftest is]]
[honey.sql :as sut]
[honey.sql.helpers
:refer [select-distinct from join left-join right-join where
group-by having order-by limit offset]]))
(def big-complicated-map
(-> (select-distinct :f.* :b.baz :c.quux [:b.bla "bla-bla"]
[[:now]] [[:raw "@x := 10"]])
(from [:foo :f] [:baz :b])
(join :draq [:= :f.b :draq.x]
:eldr [:= :f.e :eldr.t])
(left-join [:clod :c] [:= :f.a :c.d])
(right-join :bock [:= :bock.z :c.e])
(where [:or
[:and [:= :f.a "bort"] [:not= :b.baz [:param :param1]]]
[:and [:< 1 2] [:< 2 3]]
[:in :f.e [1 [:param :param2] 3]]
[:between :f.e 10 20]])
(group-by :f.a :c.e)
(having [:< 0 :f.e])
(order-by [:b.baz :desc] :c.quux [:f.a :nulls-first])
(limit 50)
(offset 10)))