Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

fix: allow LIMIT 0 for SELECT queries #918

Open
wants to merge 3 commits into
base: master
Choose a base branch
from
Open

fix: allow LIMIT 0 for SELECT queries #918

Show file tree
Hide file tree
Changes from 1 commit
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
74405b7
fix: allow LIMIT 0 for SELECT queries
ygabuev Oct 19, 2023
f2e6643
Merge branch 'uptrace:master' into master
ygabuev Jun 6, 2024
d5da368
Merge branch 'uptrace:master' into master
ygabuev Oct 23, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
53 changes: 53 additions & 0 deletions internal/dbtest/db_test.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -234,6 +234,7 @@ func TestDB(t *testing.T) {
{testNilModel},
{testSelectScan},
{testSelectCount},
{testSelectLimit},
{testSelectMap},
{testSelectMapSlice},
{testSelectStruct},
Expand Down Expand Up @@ -348,6 +349,37 @@ func testSelectCount(t *testing.T, db *bun.DB) {
require.Equal(t, 3, count)
}

func testSelectLimit(t *testing.T, db *bun.DB) {
if !db.Dialect().Features().Has(feature.CTE) {
t.Skip()
return
}

values := db.NewValues(&[]map[string]interface{}{
{"num": 1},
{"num": 2},
{"num": 3},
})

q := db.NewSelect().
With("t", values).
Column("t.num").
TableExpr("t")

var nums []int
err := q.Limit(5).Scan(ctx, &nums)
require.NoError(t, err)
require.Equal(t, 3, len(nums))

err = q.Limit(2).Scan(ctx, &nums)
require.NoError(t, err)
require.Equal(t, 2, len(nums))

err = q.Limit(0).Scan(ctx, &nums)
require.NoError(t, err)
require.Equal(t, 0, len(nums))
}

func testSelectMap(t *testing.T, db *bun.DB) {
var m map[string]interface{}
err := db.NewSelect().
Expand Down Expand Up @@ -1344,6 +1376,9 @@ func testScanAndCount(t *testing.T, db *bun.DB) {
})

t.Run("no limit", func(t *testing.T) {
err := db.ResetModel(ctx, (*Model)(nil))
require.NoError(t, err)

src := []Model{
{Str: "str1"},
{Str: "str2"},
Expand All @@ -1357,6 +1392,24 @@ func testScanAndCount(t *testing.T, db *bun.DB) {
require.Equal(t, 2, count)
require.Equal(t, 2, len(dest))
})

t.Run("limit 0", func(t *testing.T) {
err := db.ResetModel(ctx, (*Model)(nil))
require.NoError(t, err)

src := []Model{
{Str: "str1"},
{Str: "str2"},
}
_, err = db.NewInsert().Model(&src).Exec(ctx)
require.NoError(t, err)

var dest []Model
count, err := db.NewSelect().Model(&dest).Limit(0).ScanAndCount(ctx)
require.NoError(t, err)
require.Equal(t, 2, count)
require.Equal(t, 0, len(dest))
})
}

func testEmbedModelValue(t *testing.T, db *bun.DB) {
Expand Down
46 changes: 23 additions & 23 deletions query_select.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -31,7 +31,7 @@ type SelectQuery struct {
group []schema.QueryWithArgs
having []schema.QueryWithArgs
order []schema.QueryWithArgs
limit int32
limit *int32
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

let's use sql.NullInt32 here

offset int32
selFor schema.QueryWithArgs

Expand Down Expand Up @@ -313,7 +313,11 @@ func (q *SelectQuery) OrderExpr(query string, args ...interface{}) *SelectQuery
}

func (q *SelectQuery) Limit(n int) *SelectQuery {
q.limit = int32(n)
if n >= 0 {
l := int32(n)
q.limit = &l
}

return q
}

Expand Down Expand Up @@ -611,29 +615,29 @@ func (q *SelectQuery) appendQuery(
}

if fmter.Dialect().Features().Has(feature.OffsetFetch) {
if q.limit > 0 && q.offset > 0 {
if q.limit != nil && q.offset > 0 {
b = append(b, " OFFSET "...)
b = strconv.AppendInt(b, int64(q.offset), 10)
b = append(b, " ROWS"...)

b = append(b, " FETCH NEXT "...)
b = strconv.AppendInt(b, int64(q.limit), 10)
b = strconv.AppendInt(b, int64(*q.limit), 10)
b = append(b, " ROWS ONLY"...)
} else if q.limit > 0 {
} else if q.limit != nil {
b = append(b, " OFFSET 0 ROWS"...)

b = append(b, " FETCH NEXT "...)
b = strconv.AppendInt(b, int64(q.limit), 10)
b = strconv.AppendInt(b, int64(*q.limit), 10)
b = append(b, " ROWS ONLY"...)
} else if q.offset > 0 {
b = append(b, " OFFSET "...)
b = strconv.AppendInt(b, int64(q.offset), 10)
b = append(b, " ROWS"...)
}
} else {
if q.limit > 0 {
if q.limit != nil {
b = append(b, " LIMIT "...)
b = strconv.AppendInt(b, int64(q.limit), 10)
b = strconv.AppendInt(b, int64(*q.limit), 10)
}
if q.offset > 0 {
b = append(b, " OFFSET "...)
Expand Down Expand Up @@ -958,20 +962,18 @@ func (q *SelectQuery) scanAndCountConc(ctx context.Context, dest ...interface{})
var mu sync.Mutex
var firstErr error

if q.limit >= 0 {
wg.Add(1)
go func() {
defer wg.Done()
wg.Add(1)
go func() {
defer wg.Done()

if err := q.Scan(ctx, dest...); err != nil {
mu.Lock()
if firstErr == nil {
firstErr = err
}
mu.Unlock()
if err := q.Scan(ctx, dest...); err != nil {
mu.Lock()
if firstErr == nil {
firstErr = err
}
}()
}
mu.Unlock()
}
}()

wg.Add(1)
go func() {
Expand All @@ -995,9 +997,7 @@ func (q *SelectQuery) scanAndCountConc(ctx context.Context, dest ...interface{})
func (q *SelectQuery) scanAndCountSeq(ctx context.Context, dest ...interface{}) (int, error) {
var firstErr error

if q.limit >= 0 {
firstErr = q.Scan(ctx, dest...)
}
firstErr = q.Scan(ctx, dest...)

count, err := q.Count(ctx)
if err != nil && firstErr == nil {
Expand Down
Loading