SQL的动态where 拼写实现
/**
* 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();
}
测试用例
@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);
}
实行结果
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')