请问，我现在需要从几个相关联的数据表中提取数据，SQL写法如下： dm.SQLQuery7.SQL.Text:='select a.*,b.model,unitprice,brand,code,c.voucherno,code,orderqty'; dm.SQLQuery7.SQL.Append('from EMGT.HR_MASTER a,EMGT.MODEL_MASTER b,EMGT.SALES_ENTRY c'); dm.SQLQuery7.SQL.Append('where c.empno=a.empno and c.brand=b.brand and c.code=b.code '); if not (combobox1.text = '') and not (combobox2.Text = '') then dm.SQLQuery7.SQL.Append('and ( a.deptsect between ' #39 combobox1.Text #39 ' and ' #39 combobox2.Text #39 ')'); if not (combobox1.Text = '') and (combobox2.Text = '') then dm.SQLQuery7.SQL.Append('and ( a.deptsect = ' #39 combobox1.Text #39 ')'); if not (combobox2.Text = '') and (combobox1.Text = '') then dm.SQLQuery7.SQL.Append('and ( a.deptsect = ' #39 combobox2.Text #39 ')'); if not (combobox3.text = '') and not (combobox4.Text = '') then dm.SQLQuery7.SQL.Append('and ( c.code between ' #39 combobox3.Text #39 ' and ' #39 combobox4.Text #39 ')'); if not (combobox3.Text = '') and (combobox4.Text = '') then dm.SQLQuery7.SQL.Append('and ( c.code = ' #39 combobox3.Text #39 ')'); if not (combobox4.Text = '') and (combobox3.Text = '') then dm.SQLQuery7.SQL.Append('and ( c.code = ' #39 combobox4.Text #39 ')');

請問你是用哪種元件存取Oracle9i? 文章內容不完整...............

Dbexpress里面的SQLquery咯 还有一个问题一并请教： 访问几个相关联的Table，是不是每个table必须要有自己的KEY 比如说我这个SQL语句中访问的a,b,c 三个Table,a,b都有设定key,c中没有设定key,那对于where后面的语句会不会有影响，会不会是这个问题？急。。。。。。

1. 不設定PRIMARY KEY的TABLE,在Oracle照樣可以執行,只不過該TABLE中RECORD的"唯一性"是不被保證的,當你要查詢某一筆資料,卻出現兩筆以上的回傳值時,怎麼知道哪一筆才是正確的呢!!而且設為PRIMARY KEY的FIELD會自動成為預設的INDEX,在RECORD數十萬筆且沒有額外設定INDEX的情況下,會嚴重降低QUERY的速率.    2. Code利用[格式]\[#]按鈕貼上就能使用縮排,將您的Code稍微修改如下:

WITH dm.SQLQuery7.SQL DO
BEGIN
   Text:='select a.*,b.model,unitprice,brand,code,c.voucherno,code,orderqty';
   Append('from EMGT.HR_MASTER a,EMGT.MODEL_MASTER b,EMGT.SALES_ENTRY c');
   Append('where c.empno = a.empno and c.brand = b.brand and c.code = b.code ');       if (combobox1.text <> '') and (combobox2.Text <> '')
   then
      Append('and ( a.deptsect between '''   combobox1.Text   ''' and '''   combobox2.Text   ''')')
   else if (combobox1.Text <> '') and (combobox2.Text = '')
   then
      Append('and ( a.deptsect = '''   combobox1.Text   ''')')
   else if (combobox1.Text = '') and (combobox2.Text <> '')
   then
      Append('and ( a.deptsect = '''   combobox2.Text   ''')');       if (combobox3.text <> '') and (combobox4.Text <> '')
   then
      Append('and ( c.code between '''   combobox3.Text   ''' and '''   combobox4.Text   ''')')
   else if (combobox3.Text <> '') and (combobox4.Text = '')
   then
      Append('and ( c.code = '''   combobox3.Text   ''')')
   else if (combobox3.Text = '') and (combobox4.Text <> '')
   then
      Append('and ( c.code = '''   combobox4.Text   ''')');
END;

在SQL COMMAND的敘述上在下認為沒有問題.