.

reuse/golang/src/Makefile

@@ -26,3 +26,12 @@ reflect_rule_example:
 
 range_channel_example:
 	go run range_channel_example.go
+
+channel_select_1_example:
+	go run channel_select_1_example.go
+
+channel_select_2_example:
+	go run channel_select_2_example.go
+
+context_deadline_example:
+	go run context_deadline_example.go

reuse/golang/src/channel_select_1_example.go

@@ -0,0 +1,42 @@
+package main
+
+// select的default逻辑
+
+import (
+	"sync"
+	"time"
+)
+
+var wg sync.WaitGroup
+
+func main() {
+	wg.Add(1)
+	ch := make(chan string)
+
+	go func() {
+		defer wg.Done()
+
+		for _ = range [10]int{} {
+			time.Sleep(1 * time.Millisecond)
+			select {
+			case i := <-ch:
+				println(i)
+			default:
+				println("default")
+			}
+		}
+	}()
+
+	ch <- "1"
+	time.Sleep(1 * time.Millisecond)
+	ch <- "2"
+	time.Sleep(1 * time.Millisecond)
+	ch <- "3"
+	time.Sleep(1 * time.Millisecond)
+	ch <- "4"
+	time.Sleep(1 * time.Millisecond)
+	ch <- "5"
+
+	close(ch)
+	wg.Wait()
+}

reuse/golang/src/channel_select_2_example.go

@@ -0,0 +1,26 @@
+package main
+
+// channel 阻塞消费
+
+import (
+	"fmt"
+)
+
+func sum(s []int, c chan int) {
+	sum := 0
+	for _, v := range s {
+		sum += v
+	}
+	c <- sum // send sum to c
+}
+func main() {
+	s := []int{7, 2, 8, -9, 4, 0}
+	c := make(chan int)
+	go sum(s[:len(s)/2], c)
+	go sum(s[len(s)/2:], c)
+
+	// 阻塞等待
+	x, y := <-c, <-c // receive from c
+
+	fmt.Println(x, y, x+y)
+}

reuse/golang/src/channel_switch_select.go

@@ -0,0 +1,3 @@
+package main
+
+// TODO

reuse/golang/src/context_deadline_example.go

@@ -0,0 +1,25 @@
+package main
+
+// context.WithDeadline() example
+
+import (
+	"context"
+	"fmt"
+	"time"
+)
+
+func main() {
+	d := time.Now().Add(50 * time.Millisecond)
+
+	ctx, cancel := context.WithDeadline(context.Background(), d)
+
+	defer cancel()
+
+	select {
+	case <-time.After(1 * time.Second):
+		fmt.Println("overslept")
+	case <-ctx.Done():
+		fmt.Println(ctx.Err())
+
+	}
+}

reuse/sql/reuse.sql

@@ -53,6 +53,28 @@ WHERE name LIKE 'test%'
 LIMIT 10
 ;
 
+-- json get 通过key获取value
+-- {\"test\":true}
+SELECT json_col->'$.test'
+FROM t_test
+;
+
+
+-- 捞出所有重复数量等于3的id
+SELECT DISTINCT id
+FROM t_test
+GROUP BY id
+HAVING COUNT(id) = 3
+;
+
+
+-- 今天从0点开始插入的数据行数
+SELECT COUNT(*)
+FROM `t_test`
+WHERE gmt_create > DATE_FORMAT(CURDATE(),'%Y-%m-%d %H:%i:%s')
+;
+
+
 SHOW status LIKE 'Com_select%';
 SHOW status LIKE 'Com_insert%';
 SHOW status LIKE 'Com_update%';