SQL的動態where 拼寫實現
/**
* or 拼 in(num个)
* 列名
* list
* in中多少个元素
*/
public String createSql(String col, List<String> partners, int num) {
StringBuffer sb = new StringBuffer();
// COL in (1,2,3,4,5,6)
// or
// COL in (7,8,9,10,11,12)
// ->
// COL in (
// 1,2,3,4,5,6)
// or COL in (
// 7,8,9,10,11,12)
sb.append(col + " in (");
int size = partners.size();
for (int i=1;i<(size+1);i++) {
int shang = i/num;
int yushu = i%num;
if(yushu == 0){
sb.append("'" + partners.get(i-1) + "')");
if((i!=size)&&(shang != 0)){
sb.append(" or ");
sb.append(col + " in (");
}
}else{
if(i==size){
sb.append("'" + partners.get(i-1) + "')");
}else{
sb.append("'" + partners.get(i-1) + "',");
}
}
}
return sb.toString();
}
測試用例
@Test
public void test() {
List partners = new ArrayList();
partners.clear();
for (int i = 1; i < 9; i++) {
partners.add(String.valueOf(i));
}
String s = createSql("COL", partners, 10);
System.out.println(s);
/////////////////////////////////////////////////////////////////////////////////
partners.clear();
for (int i = 1; i < 10; i++) {
partners.add(String.valueOf(i));
}
s = createSql("COL", partners, 10);
System.out.println(s);
/////////////////////////////////////////////////////////////////////////////////
partners.clear();
for (int i = 1; i < 11; i++) {
partners.add(String.valueOf(i));
}
s = createSql("COL", partners, 10);
System.out.println(s);
/////////////////////////////////////////////////////////////////////////////////
partners.clear();
for (int i = 1; i < 12; i++) {
partners.add(String.valueOf(i));
}
s = createSql("COL", partners, 10);
System.out.println(s);
/////////////////////////////////////////////////////////////////////////////////
partners.clear();
for (int i = 1; i < 13; i++) {
partners.add(String.valueOf(i));
}
s = createSql("COL", partners, 10);
System.out.println(s);
/////////////////////////////////////////////////////////////////////////////////
partners.clear();
for (int i = 1; i < 20; i++) {
partners.add(String.valueOf(i));
}
s = createSql("COL", partners, 10);
System.out.println(s);
/////////////////////////////////////////////////////////////////////////////////
partners.clear();
for (int i = 1; i < 21; i++) {
partners.add(String.valueOf(i));
}
s = createSql("COL", partners, 10);
System.out.println(s);
/////////////////////////////////////////////////////////////////////////////////
partners.clear();
for (int i = 1; i < 22; i++) {
partners.add(String.valueOf(i));
}
s = createSql("COL", partners, 10);
System.out.println(s);
}
實行結果
COL in ('1','2','3','4','5','6','7','8')
COL in ('1','2','3','4','5','6','7','8','9')
COL in ('1','2','3','4','5','6','7','8','9','10')
COL in ('1','2','3','4','5','6','7','8','9','10') or COL in ('11')
COL in ('1','2','3','4','5','6','7','8','9','10') or COL in ('11','12')
COL in ('1','2','3','4','5','6','7','8','9','10') or COL in ('11','12','13','14','15','16','17','18','19')
COL in ('1','2','3','4','5','6','7','8','9','10') or COL in ('11','12','13','14','15','16','17','18','19','20')
COL in ('1','2','3','4','5','6','7','8','9','10') or COL in ('11','12','13','14','15','16','17','18','19','20') or COL in ('21')