MySQL 列属性为 JSON 时，若此列未设值，则跳过插入，避免引起错误：Invalid JSON text: "The document is empty." at position 0 in value

dialects/mysql.go

@@ -304,6 +304,7 @@ func (db *mysql) SQLType(c *schemas.Column) string {
 		c.Length = 40
 	case schemas.Json:
 		res = schemas.Text
+		c.IsJSON = true
 	case schemas.UnsignedInt:
 		res = schemas.Int
 		isUnsigned = true

session_insert.go

@@ -501,6 +501,10 @@ func (session *Session) genInsertColumns(bean interface{}) ([]string, []interfac
 			continue
 		}
 
+		if col.IsJSON && fieldValue.String() == "" {
+			continue
+		}
+
 		// !evalphobia! set fieldValue as nil when column is nullable and zero-value
 		if _, ok := getFlagForColumn(session.statement.NullableMap, col); ok {
 			if col.Nullable && utils.IsValueZero(fieldValue) {