update examples

internal/server.sql

@@ -2,6 +2,7 @@
 -- https://docs.sqlc.dev/en/latest/howto/named_parameters.html
 
 -- https://docs.sqlc.dev/en/latest/howto/insert.html
+-- https://dev.to/forbeslindesay/postgres-unnest-cheat-sheet-for-bulk-operations-1obg
 -- name: CreateOrUpdateServers :many
 INSERT INTO servers (key, url, open, version_code, config, building_info, unit_info)
 VALUES (UNNEST(@key::varchar(100)[]), UNNEST(@url::varchar(255)[]), UNNEST(@open::boolean[]),
@@ -15,6 +16,7 @@ ON CONFLICT ON CONSTRAINT servers_pkey DO UPDATE SET url  = EXCLUDED.url,
 RETURNING *;
 
 -- https://docs.sqlc.dev/en/latest/howto/select.html
+-- https://docs.sqlc.dev/en/stable/reference/changelog.html#sqlc-embed
 -- name: ListServers :many
 SELECT sqlc.embed(server), sqlc.embed(version)
 from servers server
@@ -35,10 +37,7 @@ LIMIT @pag_limit OFFSET @pag_offset;
 
 -- https://docs.sqlc.dev/en/latest/howto/query_count.html
 -- name: CountServersByVersionCode :many
-SELECT version_code, count(key)
-FROM servers server
-GROUP BY version_code
-ORDER BY version_code ASC;
+SELECT version_code::varchar, cnt::bigint from count_servers_by_version_code() res;
 
 -- https://docs.sqlc.dev/en/latest/howto/update.html
 -- name: UpdateServer :one
@@ -47,3 +46,7 @@ SET
     config = coalesce(sqlc.narg('open'), open)
 WHERE key = sqlc.arg('key')
 RETURNING *;
+
+-- https://docs.sqlc.dev/en/stable/howto/delete.html
+-- name: DeleteServer :one
+DELETE FROM servers WHERE key IN (SELECT key FROM servers WHERE player_data_updated_at IS NULL LIMIT 1) RETURNING *;

internal/version.sql

@@ -3,7 +3,9 @@
 
 -- https://docs.sqlc.dev/en/latest/howto/insert.html
 -- name: CreateVersion :one
-INSERT INTO versions (code, name, host, timezone) VALUES ($1, $2, $3, $4) RETURNING *;
+INSERT INTO versions (code, name, host, timezone)
+VALUES ($1, $2, $3, $4)
+RETURNING *;
 
 -- https://docs.sqlc.dev/en/latest/howto/select.html
 -- name: ListVersions :many
@@ -11,6 +13,15 @@ SELECT *
 from versions
 ORDER BY code ASC;
 
+-- https://docs.sqlc.dev/en/latest/howto/select.html
+-- name: ListVersionsWithServerCount :many
+SELECT sqlc.embed(v), count_servers(v.version_code) as cnt
+from versions v
+ORDER BY v.code ASC;
+
 -- https://docs.sqlc.dev/en/latest/howto/select.html
 -- name: GetVersion :one
-SELECT * from versions WHERE code = $1 LIMIT 1;
+SELECT *
+from versions
+WHERE code = $1
+LIMIT 1;

main.go

@@ -24,7 +24,7 @@ const envPostgresConnString = "POSTGRES_CONNECTION_STRING"
 
 func main() {
 	var demoName string
-	flag.StringVar(&demoName, "demo", "listVersions", "one of: listVersions, listOpenServers, createVersionAndServers, countServersByVersionCode")
+	flag.StringVar(&demoName, "demo", "listVersions", "one of: listVersions, listOpenServers, createVersionAndServers, countServersByVersionCode, deleteServer")
 
 	flag.Parse()
 
@@ -95,6 +95,8 @@ func (d demo) run(name string) error {
 		return d.createVersionAndServers()
 	case "countServersByVersionCode":
 		return d.countServersByVersionCode()
+	case "deleteServer":
+		return d.deleteServer()
 	default:
 		return errors.New("unknown demo")
 	}
@@ -193,12 +195,28 @@ func (d demo) countServersByVersionCode() error {
 	}
 
 	for _, r := range rows {
-		fmt.Printf("Version: %s\nCount: %d\n", r.VersionCode, r.Count)
+		fmt.Printf("Version: %s\nCount: %d\n", r.VersionCode, r.Cnt)
 	}
 
 	return nil
 }
 
+func (d demo) deleteServer() error {
+	s, err := d.queries.DeleteServer(context.Background())
+	if err != nil {
+		return fmt.Errorf("couldn't delete server: %w", err)
+	}
+
+	v, err := d.queries.GetVersion(context.Background(), s.VersionCode)
+	if err != nil {
+		return err
+	}
+
+	printServer(s, v)
+
+	return nil
+}
+
 func printServer(s internal.Server, v internal.Version) {
 	fmt.Printf(
 		"---%s---\nOpen: %v\nConfig: %v\nBuildingInfo: %v\nUnit info: %v\nCreated at: %s\nVersion: %s (%s)\n",

migrations/20230830065434_add_functions.sql

@@ -0,0 +1,39 @@
+-- +goose Up
+-- +goose StatementBegin
+create function count_servers(ver_code varchar)
+    returns bigint
+    language plpgsql
+as
+$$
+declare
+    cnt bigint;
+begin
+    select count(*)
+    into cnt
+    from servers
+    where version_code = ver_code;
+
+    return cnt;
+end;
+$$;
+
+create function count_servers_by_version_code()
+    returns table(version_code varchar, cnt bigint)
+    language plpgsql
+as
+$$
+begin
+    return query
+        SELECT server.version_code, count(server.key) cnt
+        FROM servers server
+        GROUP BY server.version_code
+        ORDER BY server.version_code ASC;
+end;
+$$;
+-- +goose StatementEnd
+
+-- +goose Down
+-- +goose StatementBegin
+drop function count_servers(ver_code varchar);
+drop function count_servers_by_version_code();
+-- +goose StatementEnd