数量为0的判断

2025-07-25 16:54:42 +08:00
parent cbe48f9780
commit 59de0d8ea1
6 changed files with 91 additions and 101 deletions
@@ -50,6 +50,7 @@ public interface CaseClinicalVideoDao extends BaseMapper<CaseClinicalVideoModel>
    @Update("UPDATE case_clinical_video SET ${field} = ${field} + #{numeral} WHERE video_id = #{videoId}")
    int inc(@Param("videoId") Long articleId, @Param("field") String field, @Param("numeral") int numeral);

+
    /**
     * Dec 自减
     *
@@ -58,6 +59,8 @@ public interface CaseClinicalVideoDao extends BaseMapper<CaseClinicalVideoModel>
     * @param numeral   减少的数值
     * @return 更新的行数
     */
-    @Update("UPDATE case_clinical_video SET ${field} = ${field} - #{numeral} WHERE video_id = #{videoId}")
+    @Update("UPDATE case_clinical_video " +
+            "SET ${field} = CASE WHEN ${field} >= #{numeral} THEN ${field} - #{numeral} ELSE 0 END " +
+            "WHERE video_id = #{videoId}")
    int dec(@Param("videoId") Long articleId, @Param("field") String field, @Param("numeral") int numeral);
 }