OPEN SQL 语句包含有: SELECT,INSERT,UPDATE,MODIFY,DELETE,OPEN CURSOR, FETCH,CLOSE CURSOR,COMMIT WORK,ROLLBACK WORK等.
1. SELECT语句
语法格式:
SELECT <result> [INTO <target>] [FROM <source>] [WHERE <condition>]
[GROUP BY <fields>] [ORDER BY <sort order>]
其中: <result>指定要抓取的字段
<target>将读取的记录存放在work area中
<source>指定从那个TABLE中读取资料
<condition>抓取资料的条件
<fields>指定按那些字段分组
<sort order>排序的字段及方式
相关的系统变量:
SY-SUBRC = 0 表示读取数据成功
<> 0 表示未找到符合条件的记录
SY-DBLNT: 被处理过的记录的笔数.
相关的命令:
EXIT. 退出循环.
CHECK <logistic statement>.如果逻辑表达式成立,则继续执行,否则,开
始下一次循环.
◆ .利用循环方式读取所有记录
SELECT ….ENDSELECT.是循环方式读取记录的.
例如:
TABLES MARD.
SELECT [DISTINCT] * FROM MARD WHERE MATNR = ‘3520421700’.
<Statements>.
ENDSELECT.
(从MARD中抓取所有料号=3520421700的资料)
◆读取一笔资料
TABLES MARD.
SELECT SINGLE * FROM MARD WHERE MATNR = ‘3520421700’.
(从MARA中抓取一笔料号=3520421700的资料)
◆ 将读取的记录放在work area中,并且加入Internal table 中.
格式有:
... INTO <work area>
... INTO CORRESPONDING FIELDS OF <work area>
... INTO (f1, ..., fn) 变量组.
... INTO TABLE <internal table>
... INTO CORRESPONDING FIELDS OF TABLE <internal table>
... APPENDING TABLE <internal table>
... APPENDING CORRESPONDING FIELDS OF TABLE <internal table>
举例一:
TABLES MARD.
DATA: BEGIN OF ITAB OCCURS 10,
MATNR LIKE MARD-MATNR,
WERKS LIKE MARD-WERKS,
LGORT LIKE MARD-LGORT,
LABST LIKE MARD-LABST,
END OF ITAB.
SELECT MATNR WERKS LGORT LABST
INTO CORRESPONDING FIELDS OF ITAB
FROM MARD
WHERE MATNR = ‘3520421700’.
APPEND ITAB.
CLEAR ITAB.
ENDSELECT.
(将读取的结果放在Internal table ITAB中)
举例二.
TABLES MARD.
SELECT MATNR MTART MAKTX INTO (t_matnr, t_mtart, maktx)
FROM MARD
WHERE MATNR = ‘3520421700’.
<Statements>.
ENDSELECT.
(从MARD中抓取料号=3520421700的料号、类型和描述,放在变量t_matnr, t_mtart, maktx中)。
◆按指定的字段排序
TABLES SBOOK.
SELECT * FROM SBOOK WHERE CARRID = ‘LH’ AND
CONNID = ‘0400’ AND
FLDATE = ‘19950228’
ORDER BY BOOKID [ASCENDING/DESCENDING].
WRITE: / SBOOK-BOOKID, SBOOK-CUSTOMID,
SBOOK-CUSTTYPE, SBOOK-SMOKER,
SBOOK-LUGGWEIGHT, SBOOK-WUNIT,
SBOOK-INVOICE.
ENDSELECT.
(利用参数ORDER BY所指定的字段排序)
◆ 抓取数据的条件叙述
(1) BETWEEN <g1> AND <g2>
例如: WHERE YEAR BETWEEN 1995 AND 2000.
(2) LIKE <g>
例如: WHERE NAME LIKE ‘MIKE%’.
(‘%’是通配符号)
(3) IN (<g1>…<gn>)
是<g1>…<gn>里面的任意一个值即可.
例如: WHERE PLANT IN (‘CHUNGLI’, ‘TAOYUAN’,’LIUTU’).
(表示PLANT 只要是’CHUNGLI’或’TAOYUAN’或’LIUTU’都可以).
2. INSERT 语句
◆ 从work area 加入到Internal Table中
格式: INSERT INTO <database> VALUES <work area>
例如:
DATA: BEGIN OF WA,
CODE(6) TYPE C,
NAME(30) TYPE C,
END OF WA.
DATA: VEN LIKE WA OCCURS 10.
…
WA-CODE = ‘530120’.
WA-NAME = ‘XINGDA ELECTRONICS CO.,LTD’.
INSERT INTO VEN VALUES WA .
如果work area的名称就是internal table的名称,可以直接写成:
INSERT <internal table>
例如:
DATA: BEGIN OF WA OCCURS 10,
CODE(6) TYPE C,
NAME(30) TYPE C,
END OF WA.
…
WA-CODE = ‘530120’.
WA-NAME = ‘XINGDA ELECTRONICS CO., LTD’.
INSERT WA.
◆ 从另外一个Internal table中INSERT 资料
格式:
INSERT <itab1> FROM TABLE <itab2> [ACCEPTING DUPLICATE KEY]
将<itab2>中非NULL的资料加入<itab1>中,加上[ACCEPTING DUPLICATE KEY]能限制相同PRIMARY KEY不重复加入.
3. MODIFY 语法
MODIFY <internal table> [FROM <work area>].
4. DELETE 语法
DELETE <internal table> [FROM <work area>].
或: DELETE <internal table> [WHERE <conditions>]
5. DATABASE CURSOR
Database Cursor是一个数据库暂存区, 将经SELECT指令读取的记录存放至此暂存区, 再由此暂存区放至Work Area中, 可减少数据库读取的次数.
1.开启 Database Cursor
语法:
OPEN CURSOR <c> FOR SELECT … WHERE <condition>
Example:
TABLES SPFLI.
DATA: WA LIKE SPFLI,
C1 TYPE CURSOR.
OPEN CURSOR C1 FOR SELECT * FROM SPFLI
WHERE AREA =’TAIWAN’.
2.读取 Database Cursor的资料存入 Work Area
语法:
FETCH NEXT CURSOR <c> INTO <wa>
Example:
FETCH NEXT CURSOR C1 INTO WA.
读取下一笔Cursor位置的数据存入WA, 如果已无资料可读, SY-SUBRC <>0.
关闭 Database Cursor
语法:
CLOSE CURSOR <c>
Example:
CLOSE CURSOR C1.
6. COMMIT WORK & ROLLBACK WORK
要确定资料成功写入数据库,可使用COMMIT WORK指令,如:
COMMIT WORK.
相反的, 如果反悔要复原, 可使用 ROLLBACK WORK, 可复原在上个COMMIT WORK指令之后的数据, 如:
ROLLBACK WORK.
本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/shin_zhong/archive/2009/09/18/4568358.aspx