add first try test with mat view

dal/dal.go

@@ -197,9 +197,12 @@ func NewClickHouseDAL(ctx context.Context, cred string) (*ClickHouseDAL, error)
 		return nil, fmt.Errorf("error ping database: %w", err)
 	}
 
-	statsClickRepo := statistics.NewClickStatistic(statistics.DepsClick{
+	statsClickRepo, err := statistics.NewClickStatistic(ctx, statistics.DepsClick{
 		Conn: conn,
 	})
+	if err != nil {
+		return nil, err
+	}
 
 	return &ClickHouseDAL{
 		conn:               conn,

repository/statistics/click_statistics.go

@@ -1,6 +1,10 @@
 package statistics
 
-import "database/sql"
+import (
+	"context"
+	"database/sql"
+	"fmt"
+)
 
 type DepsClick struct {
 	Conn *sql.DB
@@ -10,8 +14,94 @@ type StatisticClick struct {
 	conn *sql.DB
 }
 
-func NewClickStatistic(deps DepsClick) *StatisticClick {
+func NewClickStatistic(ctx context.Context, deps DepsClick) (*StatisticClick, error) {
-	return &StatisticClick{
+	s := &StatisticClick{
 		conn: deps.Conn,
 	}
+
+	err := s.checkMW(ctx)
+	if err != nil {
+		fmt.Println("error check material view existing")
+		return nil, err
+	}
+
+	return s, nil
+}
+
+func (s *StatisticClick) checkMW(ctx context.Context) error {
+	query := `
+CREATE MATERIALIZED VIEW IF NOT EXISTS mv_last_answers_events
+ENGINE = MergeTree()
+PARTITION BY toStartOfDay(event_time)
+ORDER BY (ctxsession, event_time) AS
+SELECT
+    event_time,ctxsession,ctxquizid,ctxquestionid,ctxidint,message,keyos,keydevice,keydevicetype,
+    keybrowser,ctxuserip,ctxuserport,keydomain,keypath,ctxquiz,ctxreferrer
+FROM statistics WHERE message IN ('InfoQuizOpen', 'InfoAnswer', 'InfoResult')
+  AND event_level = 'info' AND create_time = (SELECT max(create_time) FROM statistics AS inner_table 
+      WHERE inner_table.ctxsession = statistics.ctxsession);
+`
+	_, err := s.conn.ExecContext(ctx, query)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+type PipeLineStatsResp [][]struct {
+	Count      int64
+	QuestionID int64
+}
+
+func (s *StatisticClick) GetPipelinesStatistics(ctx context.Context, from uint64, to uint64) ([]PipeLineStatsResp, error) {
+	query := `
+SELECT
+    ctxsession,ctxquestionid,count(*) as session_count
+FROM mv_last_answers_events WHERE event_time BETWEEN ? AND ?
+GROUP BY ctxsession, ctxquestionid ORDER BY ctxsession, ctxquestionid
+`
+	rows, err := s.conn.QueryContext(ctx, query, from, to)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	var pipelines []PipeLineStatsResp
+	var currentPipeline PipeLineStatsResp
+	var lastSession string
+
+	for rows.Next() {
+		var session string
+		var questionID int64
+		var count int64
+		err := rows.Scan(&session, &questionID, &count)
+		if err != nil {
+			return nil, err
+		}
+
+		// новая сессия - новая воронка
+		if session != lastSession && lastSession != "" {
+			pipelines = append(pipelines, currentPipeline)
+			currentPipeline = PipeLineStatsResp{}
+		}
+
+		// текущая статистика в текущую воронку
+		currentPipeline = append(currentPipeline, []struct {
+			Count      int64
+			QuestionID int64
+		}{{Count: count, QuestionID: questionID}})
+
+		lastSession = session
+	}
+
+	// последня воронка если есть то добавляем
+	if len(currentPipeline) > 0 {
+		pipelines = append(pipelines, currentPipeline)
+	}
+
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+
+	return pipelines, nil
 }