Compare · 001

Your first query: MySQL and ClickHouse

Every file of the MySQL and ClickHouse versions side by side, with the lines that differ marked. 3 parameter or column types differ in Go.

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Configuration

sgl.yamldiffers
MySQL
ClickHouse
1version: 1
1version: 1
2
2
3databases:
3databases:
4 - name: tasks
4 - name: tasks
5 dialect: mysql
5 dialect: clickhouse
6 migrations: db/migrations
6 migrations: db/migrations
7 queries: db/queries
7 queries: db/queries
8 go:
8 go:
9 package: store
9 package: store
10 out: internal/store
10 out: internal/store

Migrations

db/migrations/0001_init.up.sqldiffers
MySQL
ClickHouse
1CREATE TABLE tasks (
1CREATE TABLE tasks (
2 id BIGINT NOT NULL AUTO_INCREMENT PRIMARY KEY,
2 id UInt64,
3 title VARCHAR(200) NOT NULL,
3 title String,
4 completed INT NOT NULL DEFAULT 0,
4 completed UInt8 DEFAULT 0,
5 created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
5 created_at DateTime DEFAULT now()
6);
6) ENGINE = MergeTree() ORDER BY id;
db/migrations/0001_init.down.sqlidentical
MySQL
ClickHouse
1DROP TABLE tasks;
1DROP TABLE tasks;

Queries

CreateTaskdiffers
MySQL · db/queries/tasks.sql
ClickHouse · db/queries/tasks.sql
1-- sgl.query(CreateTask, execresult)
1-- sgl.query(CreateTask, exec)
2INSERT INTO tasks (title) VALUES (?);
2INSERT INTO tasks (id, title) VALUES ({id:UInt64}, {title:String});
ListTasksidentical
MySQL · db/queries/tasks.sql
ClickHouse · db/queries/tasks.sql
1-- sgl.query(ListTasks, many)
1-- sgl.query(ListTasks, many)
2SELECT id, title, completed, created_at FROM tasks ORDER BY id;
2SELECT id, title, completed, created_at FROM tasks ORDER BY id;
CompleteTaskdiffers
MySQL · db/queries/tasks.sql
ClickHouse · db/queries/tasks.sql
1-- sgl.query(CompleteTask, execrows)
1-- sgl.query(CompleteTask, asyncexec)
2UPDATE tasks SET completed = 1 WHERE id = ?;
2ALTER TABLE tasks UPDATE completed = 1 WHERE id = {id:UInt64};
GetTaskonly ClickHouse
MySQL · not in this version
ClickHouse · db/queries/tasks.sql
1-- sgl.query(GetTask, one)
2SELECT id, title, completed, created_at FROM tasks WHERE id = {id:UInt64};

What sgl generates

CreateTaskdiffers
MySQL
ClickHouse
1func (queries *Queries) CreateTask(ctx context.Context, title string) (sql.Result, error)
1func (queries *Queries) CreateTask(ctx context.Context, params CreateTaskParams) error
2
3type CreateTaskParams struct {
4 ID uint64
5 Title string
6}
ListTasksdiffers
MySQL
ClickHouse
1func (queries *Queries) ListTasks(ctx context.Context) ([]ListTasksRow, error)
1func (queries *Queries) ListTasks(ctx context.Context) ([]ListTasksRow, error)
2
2
3type ListTasksRow struct {
3type ListTasksRow struct {
4 ID int64 `json:"id"`
4 ID uint64 `json:"id"`
5 Title string `json:"title"`
5 Title string `json:"title"`
6 Completed int32 `json:"completed"`
6 Completed uint8 `json:"completed"`
7 CreatedAt time.Time `json:"created_at"`
7 CreatedAt time.Time `json:"created_at"`
8}
8}
CompleteTaskdiffers
MySQL
ClickHouse
1func (queries *Queries) CompleteTask(ctx context.Context, id int64) (int64, error)
1func (queries *Queries) CompleteTask(ctx context.Context, id uint64) error
GetTaskonly ClickHouse
MySQL · not in this version
ClickHouse
1func (queries *Queries) GetTask(ctx context.Context, id uint64) (GetTaskRow, error)
2
3type GetTaskRow struct {
4 ID uint64 `json:"id"`
5 Title string `json:"title"`
6 Completed uint8 `json:"completed"`
7 CreatedAt time.Time `json:"created_at"`
8}

The program

example.godiffers
MySQL
ClickHouse
1package main
1package main
2
2
3import (
3import (
4 "context"
4 "context"
5 "database/sql"
5 "database/sql"
6 "fmt"
6 "fmt"
7 "io"
7 "io"
8
8
9 "seagull.sh/seagull/examples/mysql/001_first_query/internal/store"
9 "seagull.sh/seagull/examples/clickhouse/001_first_query/internal/store"
10)
10)
11
11
12// run adds two tasks, completes the first and lists them all, through the methods sgl
12// run adds two tasks, completes the first and lists them all, through the methods sgl
13// generated from db/queries/tasks.sql.
13// generated from db/queries/tasks.sql.
14//
14//
15// MySQL has no RETURNING, so CreateTask is execresult: it returns the driver's
15// ClickHouse has no auto-increment and no RETURNING, so the caller chooses each task's id
16// sql.Result, and LastInsertId gives the AUTO_INCREMENT id MySQL assigned. The id column
16// and reads a task back with GetTask. CompleteTask uses ALTER TABLE ... UPDATE, which
17// is BIGINT, so it is an int64 like LastInsertId's result and needs no conversion.
17// queues a mutation that the server applies in the background, so the query is declared
18// asyncexec and returns only an error (concept 36 explains why). The connection sets
19// mutations_sync=2, which makes the server finish the mutation before it replies, so the
20// list below already shows the task completed.
18//
21//
19// Takes database (*sql.DB) which is a migrated database.
22// Takes database (*sql.DB) which is a migrated database.
20// Takes output (io.Writer) which receives the task list.
23// Takes output (io.Writer) which receives the task list.
21//
24//
22// Returns error when a query fails.
25// Returns error when a query fails.
23func run(ctx context.Context, database *sql.DB, output io.Writer) error {
26func run(ctx context.Context, database *sql.DB, output io.Writer) error {
24 queries := store.New(database)
27 queries := store.New(database)
25
28
26 result, err := queries.CreateTask(ctx, "Feed the seagulls")
29 tasks := []store.CreateTaskParams{
27 if err != nil {
30 {ID: 1, Title: "Feed the seagulls"},
28 return fmt.Errorf("creating a task: %w", err)
31 {ID: 2, Title: "Count the chips"},
29 }
30 feed, err := result.LastInsertId()
31 if err != nil {
32 return fmt.Errorf("reading the new task's id: %w", err)
33 }
32 }
34 if _, err := queries.CreateTask(ctx, "Count the chips"); err != nil {
33 for _, task := range tasks {
35 return fmt.Errorf("creating a task: %w", err)
34 if err := queries.CreateTask(ctx, task); err != nil {
35 return fmt.Errorf("creating task %d: %w", task.ID, err)
36 }
36 }
37 }
37
38
38 completed, err := queries.CompleteTask(ctx, feed)
39 feed, err := queries.GetTask(ctx, 1)
39 if err != nil {
40 if err != nil {
40 return fmt.Errorf("completing task %d: %w", feed, err)
41 return fmt.Errorf("getting task 1: %w", err)
41 }
42 }
42 fmt.Fprintf(output, "completed %d task\n", completed)
43 fmt.Fprintf(output, "created task %d, %s\n", feed.ID, feed.Title)
43
44
44 tasks, err := queries.ListTasks(ctx)
45 if err := queries.CompleteTask(ctx, feed.ID); err != nil {
46 return fmt.Errorf("completing task %d: %w", feed.ID, err)
47 }
48 fmt.Fprintf(output, "completed task %d\n", feed.ID)
49
50 listed, err := queries.ListTasks(ctx)
45 if err != nil {
51 if err != nil {
46 return fmt.Errorf("listing tasks: %w", err)
52 return fmt.Errorf("listing tasks: %w", err)
47 }
53 }
48 for _, task := range tasks {
54 for _, task := range listed {
49 fmt.Fprintf(output, "%d\t%-18s completed=%d\n", task.ID, task.Title, task.Completed)
55 fmt.Fprintf(output, "%d\t%-18s completed=%d\n", task.ID, task.Title, task.Completed)
50 }
56 }
51 return nil
57 return nil
52}
58}

Go type differences

The same SQL types map to different Go types, because each database reports them differently.

QueryFieldMySQLClickHouse
ListTaskscolumn idint64uint64
ListTaskscolumn completedint32uint8
CompleteTaskparameter idint64uint64