From c50f87cb9b9c252ffc85449780dce7996fe4035e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Carlos=20Nieto?= <jose.carlos@menteslibres.net>
Date: Thu, 7 Aug 2014 11:24:37 -0500
Subject: [PATCH] PostgreSQL: Adding support for db.Result.Group().
---
postgresql/_dumps/structs.sql | 8 +++++
postgresql/database.go | 1 +
postgresql/database_test.go | 55 +++++++++++++++++++++++++++++++++++
postgresql/layout.go | 8 +++++
postgresql/result.go | 23 ++++++++++++++-
5 files changed, 94 insertions(+), 1 deletion(-)
diff --git a/postgresql/_dumps/structs.sql b/postgresql/_dumps/structs.sql
index 6da53ad6..8e0f0551 100644
--- a/postgresql/_dumps/structs.sql
+++ b/postgresql/_dumps/structs.sql
@@ -44,3 +44,11 @@ CREATE TABLE data_types (
_date timestamp without time zone,
_time time without time zone
);
+
+DROP TABLE IF EXISTS stats_test;
+
+CREATE TABLE stats_test (
+ id serial primary key,
+ numeric integer,
+ value integer
+);
diff --git a/postgresql/database.go b/postgresql/database.go
index 77231477..7e56921a 100644
--- a/postgresql/database.go
+++ b/postgresql/database.go
@@ -108,6 +108,7 @@ func init() {
pgsqlDropDatabaseLayout,
pgsqlDropTableLayout,
pgsqlSelectCountLayout,
+ pgsqlGroupByLayout,
}
db.Register(Adapter, &source{})
diff --git a/postgresql/database_test.go b/postgresql/database_test.go
index 09e6a740..578fb222 100644
--- a/postgresql/database_test.go
+++ b/postgresql/database_test.go
@@ -31,6 +31,7 @@ package postgresql
import (
"database/sql"
"flag"
+ "math/rand"
"os"
"reflect"
"strings"
@@ -678,7 +679,61 @@ func TestNullableFields(t *testing.T) {
if test.NullStringTest.Valid == false {
t.Fatalf(`Expecting valid value.`)
}
+}
+
+func TestGroup(t *testing.T) {
+
+ var err error
+ var sess db.Database
+ var stats db.Collection
+
+ if sess, err = db.Open(Adapter, settings); err != nil {
+ t.Fatal(err)
+ }
+
+ type stats_t struct {
+ Numeric int `db:"numeric"`
+ Value int `db:"value"`
+ }
+
+ defer sess.Close()
+
+ if stats, err = sess.Collection("stats_test"); err != nil {
+ t.Fatal(err)
+ }
+
+ // Truncating table.
+ if err = stats.Truncate(); err != nil {
+ t.Fatal(err)
+ }
+
+ // Adding row append.
+ for i := 0; i < 1000; i++ {
+ numeric, value := rand.Intn(10), rand.Intn(100)
+ if _, err = stats.Append(stats_t{numeric, value}); err != nil {
+ t.Fatal(err)
+ }
+ }
+ // db.Func{"COUNT", 1},
+ // db.Func{"SUM", `value`},
+
+ // Testing GROUP BY
+ res := stats.Find().Select(
+ `numeric`,
+ db.Raw{`COUNT(1) AS counter`},
+ db.Raw{`SUM(value) AS total`},
+ ).Group(`numeric`)
+
+ var results []map[string]interface{}
+
+ if err = res.All(&results); err != nil {
+ t.Fatal(err)
+ }
+
+ if len(results) != 10 {
+ t.Fatalf(`Expecting exactly 10 results, this could fail, but it's very unlikely to happen.`)
+ }
}
// Attempts to delete previously added rows.
diff --git a/postgresql/layout.go b/postgresql/layout.go
index a0c326b5..7f4d62ff 100644
--- a/postgresql/layout.go
+++ b/postgresql/layout.go
@@ -65,6 +65,8 @@ const (
{{.Where}}
+ {{.GroupBy}}
+
{{.OrderBy}}
{{if .Limit}}
@@ -122,5 +124,11 @@ const (
DROP TABLE {{.Table}}
`
+ pgsqlGroupByLayout = `
+ {{if .GroupColumns}}
+ GROUP BY {{.GroupColumns}}
+ {{end}}
+ `
+
psqlNull = `NULL`
)
diff --git a/postgresql/result.go b/postgresql/result.go
index 24b3f16b..37f1523a 100644
--- a/postgresql/result.go
+++ b/postgresql/result.go
@@ -43,6 +43,7 @@ type result struct {
columns sqlgen.Columns
where sqlgen.Where
orderBy sqlgen.OrderBy
+ groupBy sqlgen.GroupBy
arguments []interface{}
}
@@ -59,6 +60,7 @@ func (self *result) setCursor() error {
Offset: self.offset,
Where: self.where,
OrderBy: self.orderBy,
+ GroupBy: self.groupBy,
}, self.arguments...)
}
return err
@@ -83,6 +85,25 @@ func (self *result) Skip(n uint) db.Result {
return self
}
+// Used to group results that have the same value in the same column or columns.
+func (self *result) Group(fields ...interface{}) db.Result {
+
+ groupByColumns := make(sqlgen.GroupBy, 0, len(fields))
+
+ l := len(fields)
+ for i := 0; i < l; i++ {
+ switch value := fields[i].(type) {
+ // Maybe other types?
+ default:
+ groupByColumns = append(groupByColumns, sqlgen.Column{value})
+ }
+ }
+
+ self.groupBy = groupByColumns
+
+ return self
+}
+
// Determines sorting of results according to the provided names. Fields may be
// prefixed by - (minus) which means descending order, ascending order would be
// used otherwise.
@@ -243,7 +264,7 @@ func (self *result) Close() error {
return err
}
-// Counting the elements that will be returned.
+// Counts the elements within the main conditions of the set.
func (self *result) Count() (uint64, error) {
var count counter_t
--
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