分页插件稍作调整

mybatis-plus/src/main/java/com/baomidou/mybatisplus/plugins/PaginationInterceptor.java

@@ -95,11 +95,7 @@ public class PaginationInterceptor implements Interceptor {
 			}
 
 			/*
-			 * <p>
-			 * 禁用内存分页
-			 * </p>
-			 * <p>
-			 * 内存分页会查询所有结果出来处理（这个很吓人的），如果结果变化频繁这个数据还会不准。
+			 * <p> 禁用内存分页 </p> <p> 内存分页会查询所有结果出来处理（这个很吓人的），如果结果变化频繁这个数据还会不准。
 			 * </p>
 			 */
 			BoundSql boundSql = (BoundSql) metaStatementHandler.getValue("delegate.boundSql");
@@ -126,21 +122,25 @@ public class PaginationInterceptor implements Interceptor {
 					 */
 					StringBuffer countSql = new StringBuffer("SELECT COUNT(1) AS TOTAL ");
 					if (page.isOptimizeCount()) {
-						String tempSql = new String(originalSql);
+						String tempSql = originalSql.replaceAll("(?i)ORDER[\\s]+BY", "ORDER BY");
 						String indexOfSql = originalSql.toUpperCase();
-						int formIndex = indexOfSql.indexOf("FROM");
-						int orderByIndex = indexOfSql.lastIndexOf("ORDER BY");
-						if (formIndex > -1) {
-							// 无排序情况处理
-							if (orderByIndex > -1) {
-								tempSql = originalSql.substring(0, orderByIndex);
-								countSql.append(tempSql.substring(formIndex));
-								orderBy = false;
+						if (!indexOfSql.contains("DISTINCT")) {
+							int formIndex = indexOfSql.indexOf("FROM");
+							int orderByIndex = indexOfSql.lastIndexOf("ORDER BY");
+							if (formIndex > -1) {
+								// 无排序情况处理
+								if (orderByIndex > -1) {
+									tempSql = originalSql.substring(0, orderByIndex);
+									countSql.append(tempSql.substring(formIndex));
+									orderBy = false;
+								} else {
+									countSql.append(originalSql.substring(formIndex));
+								}
 							} else {
-								countSql.append(originalSql.substring(formIndex));
+								countSql.append("FROM (").append(tempSql).append(") A");
 							}
 						} else {
-							countSql.append("FROM (").append(tempSql).append(") A");
+							countSql.append("FROM (").append(originalSql).append(") A");
 						}
 					} else {
 						countSql.append("FROM (").append(originalSql).append(") A");