update

cmd/dbdiag/main.go

@@ -0,0 +1,79 @@
+// 临时诊断：对照测试列元信息查询的"参数版"与"内联版"，定位 42601。
+package main
+
+import (
+	"database/sql"
+	"fmt"
+	"log"
+	"strings"
+
+	_ "github.com/jackc/pgx/v5/stdlib"
+
+	"fashionapi/internal/config"
+)
+
+func main() {
+	cfg, err := config.Load("")
+	if err != nil {
+		log.Fatalf("load config: %v", err)
+	}
+	db, err := sql.Open("pgx", cfg.Database.DSN())
+	if err != nil {
+		log.Fatalf("open: %v", err)
+	}
+	defer db.Close()
+	if err := db.Ping(); err != nil {
+		log.Fatalf("ping: %v", err)
+	}
+
+	base := `
+		SELECT c.column_name,
+		       c.udt_name,
+		       (c.is_nullable = 'YES'),
+		       COALESCE(c.column_default, ''),
+		       (c.column_default LIKE 'nextval(%')
+		FROM information_schema.columns c
+		WHERE c.table_schema = 'public' AND c.table_name = %s
+		ORDER BY c.ordinal_position`
+
+	// (a) 参数版：用 $1
+	paramQ := strings.Replace(base, "%s", "$1", 1)
+	fmt.Println("=== (a) 参数版 $1 ===")
+	testQ(db, paramQ, "brand")
+
+	// (b) 内联版：把 'brand' 直接拼进 SQL（模拟 simple-protocol 内联）
+	inlineQ := strings.Replace(base, "%s", "'brand'", 1)
+	fmt.Println("=== (b) 内联版 'brand' ===")
+	testQ(db, inlineQ)
+
+	// (c) 去掉 LIKE 表达式的版本（用 is_identity 代替）
+	noLike := `
+		SELECT c.column_name,
+		       c.udt_name,
+		       (c.is_nullable = 'YES'),
+		       COALESCE(c.column_default, ''),
+		       (c.is_identity = 'YES')
+		FROM information_schema.columns c
+		WHERE c.table_schema = 'public' AND c.table_name = 'brand'
+		ORDER BY c.ordinal_position`
+	fmt.Println("=== (c) 去掉 LIKE 表达式版 ===")
+	testQ(db, noLike)
+}
+
+func testQ(db *sql.DB, q string, args ...any) {
+	rows, err := db.Query(q, args...)
+	if err != nil {
+		fmt.Printf("  ERROR: %v\n", err)
+		// 尝试用 pgconn 解析 position
+		var pgErr interface{ Error() string }
+		_ = pgErr
+		fmt.Printf("  raw err: %s\n", err.Error())
+		return
+	}
+	cnt := 0
+	for rows.Next() {
+		cnt++
+	}
+	fmt.Printf("  OK rows=%d err=%v\n", cnt, rows.Err())
+	rows.Close()
+}