| 编号 | 类别 | ORACLE | MYSQL | 注释 |
| 1 | 内连接的更改 |
1、 select a.*, b.*, c.*, d.* from a, b, c, d where a.id = b.id and a.name is not null and a.id = c.id(+) and a.id = d.id(+) "(+)"所在位置的另一侧为连接的方向， 所以上面的例子1是左连接。 以下的例子2既是右连接。 2、 select a.*, b.*, c.*, d.* from a, b, c, d where a.id = b.id and a.name is not null and a.id(+) = c.id |
方法一 select a.*, c.*, d.* from a left join(c, d) on (a.id = c.id and a.id = d.id), b where a.id = b.id and a.name is not null 方法二 select a.*, c.*, d.* from a left join c on a.id = c.id left join d on a.id = d.id, b where a.id = b.id and a.name is not null | oracle sql语句和mysql sql语句有一定的区别. 1. oracle左连接,右连接可以使用(+)来实现. Mysql只能使用left join ,right join等关键字. |
| 2 | 最后一句执行的sql statement所取得或 影响的条数 | SQL%ROWCOUNT | 执行select语句后用: FOUND_ROWS() 执行update delete insert语句后用: ROW_COUNT(). | oracle中: sql 表示最后一句执行的 SQL Statement, rowcount表示該 SQL 所取得或影响的条数. Mysql中: 执行select语句后查询所影响的条数用: FOUND_ROWS() 执行update delete insert语句后查询所影响的条数用: ROW_COUNT() |
| 3 | 查询分页 | SELECT t1.* FROM (SELECT MSG_INT_KEY, MSG_TY, MSG_CD, ROWNUM ROW_NUM FROM SD_SYS_MSG WHERE (ii_msg_int_key IS NULL OR msg_int_key = ii_msg_int_key) ORDER BY MSG_CD ) t1 WHERE (in_page_no IS NULL) OR (t1.ROW_NUM > ((in_page_no -1)*li_per_page_amt) AND t1.ROW_NUM < (in_page_no*li_per_page_amt + 1) ); | 方法:使用循环变量替换oracle中ROWNUM set @mycnt = 0; SELECT (@mycnt := @mycnt + 1) as ROW_NUM,t1.* FROM (SELECT MSG_INT_KEY, MSG_TY, MSG_CD, ROWNUM ROW_NUM FROM SD_SYS_MSG WHERE (ii_msg_int_key IS NULL OR msg_int_key = ii_msg_int_key ) ORDER BY MSG_CD ) t1 WHERE (in_page_no IS NULL) OR (t1.ROW_NUM> ((in_page_no - 1) * li_per_page_amt) AND t1.ROW_NUM < (in_page_no * li_per_page_amt + 1) ); | |
| 4 | java null值 | ""作为参数传入后,在oracle中将识别为null | ""作为参数据传mysql还是"" | 现在java代码需要修改: inPara.add(MSG_TY.equals("") ? null : MSG_TY); |
| 5 | 执行动态sql | lv_sql := 'SELECT ' ||' distinct ' || iv_cd_field_name || ' FIELD1 '|| ' FROM ' || iv_table_name || ' WHERE ' || NVL(iv_where_cause,' 1=1 '); OPEN l_sys_cur FOR lv_sql; | set @a = iv_cd_field_name; set @b = iv_table_name; set @c = IFNULL(iv_where_cause,' 1=1 '); SET @s = concat('SELECT distinct ', @a , ' FIELD1 FROM ' , @b , ' WHERE ' , IFNULL(@c,' 1=1 ')); PREPARE stmt3 FROM @s; EXECUTE stmt3; DEALLOCATE PREPARE stmt3; | 1. oracle可以将动态sql放在游标中执行. mysql游标声明有一定的局限性: mysql游标必须在声明处理程序之前被声明，并且变量和条件必须在声明光标或处理程序之前被声明。Mysql采用Prepared Statements实现动态sql. 例子如下: INT Emp_id_var = 56 PREPARE SQLSA FROM "DELETE FROM employee WHERE emp_id=?" ; EXECUTE SQLSA USING :Emp_id_var ; |
| 6 | 存储过程相互调用时传递数组 | oracle使用数组步骤: 1. 将传入的字符串通过P_UNPACK_LIST方法转换为数组.(lo_holiday_jan_upl即为数组) P_UNPACK_LIST(iv_jan__str, lv_delimiter, lo_holiday_jan_upl); 2. 传数组到另一个存储过程. P_MOD_MONTH(iv_year, 1, lo_holiday_jan_upl, iv_user_cd); 3. P_MOD_MONTH中使用数组: (将数组中的各个元素取出来插入到SD_HOLIDAY表) FOR li_cnt IN 0 .. 9 LOOP IF iv_daystr(li_cnt) IS NOT NULL THEN INSERT INTO SD_HOLIDAY (HOLIDAY_INT_KEY, YEAR, MONTH, DAY, ENABLE_FLAG, CREATE_BY, CREATE_DATE, LAST_UPD_BY, LAST_UPD_DATE) VALUES (SEQ_HOLIDAY_INT_KEY.NEXTVAL, iv_year, iv_month, iv_daystr(li_cnt), 1, iv_user_cd, ld_sys_date, iv_user_cd, ld_sys_date); END IF; END LOOP; | mysql中数用数组步骤: 1. 将需要处理的字符串交给执行业务逻辑 的存储过程处理. CALL SD_HOLIDAY_P_MOD_MONTH(iv_year, 1, iv_jan__str, iv_user_cd); 2. SD_HOLIDAY_P_MOD_MONTH中处理字符串. (将字符串按自定格式分隔出来,在对每个小字符串进行业务逻辑处理.) SET lv_inputstr = iv_inputstr; loopLable:LOOP IF li_cnt > 9 THEN LEAVE looplable; ELSE SET li_pos = INSTR(lv_inputstr, iv_delimiter); IF li_pos = 0 THEN leave looplable; ELSE set temp_str = SUBSTR(lv_inputstr, 1, li_pos - 1); /*插入temp_str到SD_HOLIDAY表*/ INSERT INTO SD_HOLIDAY(...) SET lv_inputstr = SUBSTRING(lv_inputstr, li_pos + LENGTH(iv_delimiter)); END IF; SET li_cnt = li_cnt+1; END IF; END LOOP loopLable; | 存储过程相互调用时传递数组解决方法: oracle中传入12个字符串到存储过程,然后将这12个字符串转换为12个数组,再调用其他存储过程并将这12个数组分别传给存储过程,便利每个数组进行业务逻辑处理. mysql解决方法: 将存储过程中的数组去掉,两个存储过程调用时直接传递字符串,然后再需要处理业务逻辑的地方将字符串分解,进行业务逻辑处理. 可以参考<<2009002-OTMPPS-Difficult Questions-0001.doc>> 中 2.4.2 逐层分解字符串 |
| 7 | Java无法以String来接取int | select fac_unit_key FILED1在oracle可以 | select fac_unit_key FILED1在mysql中要改 select CAST(fac_unit_key AS CHAR) FILED1 | CAST(intvalue AS CHAR) |
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