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fix: 修复union sql的分页查询问题

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This commit is contained in:
cyb 2024-08-22 16:56:40 +08:00
parent 417b04838b
commit e170e57f55
2 changed files with 114 additions and 10 deletions
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47
mybatis-flex-core/src/main/java/com/mybatisflex/core/util/MapperUtil.java
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@ -25,13 +25,7 @@ import com.mybatisflex.core.field.FieldQuery;
import com.mybatisflex.core.field.FieldQueryBuilder;
import com.mybatisflex.core.field.FieldQueryManager;
import com.mybatisflex.core.paginate.Page;
import com.mybatisflex.core.query.CPI;
import com.mybatisflex.core.query.DistinctQueryColumn;
import com.mybatisflex.core.query.Join;
import com.mybatisflex.core.query.QueryColumn;
import com.mybatisflex.core.query.QueryCondition;
import com.mybatisflex.core.query.QueryTable;
import com.mybatisflex.core.query.QueryWrapper;
import com.mybatisflex.core.query.*;
import com.mybatisflex.core.relation.RelationManager;
import com.mybatisflex.core.table.TableInfo;
import com.mybatisflex.core.table.TableInfoFactory;
@ -75,13 +69,36 @@ public class MapperUtil {
.select(count().as("total"))
.from(queryWrapper).as("t");
}
public static QueryWrapper rawCountQueryWrapper(QueryWrapper queryWrapper,List<QueryColumn> customCountColumns) {
return customCountColumns!=null?QueryWrapper.create()
.select(customCountColumns)
.from(queryWrapper).as("t"):rawCountQueryWrapper(queryWrapper);
}
/**
* 优化 COUNT 查询语句。
*/
public static QueryWrapper optimizeCountQueryWrapper(QueryWrapper queryWrapper) {
return optimizeCountQueryWrapper(queryWrapper, Collections.singletonList(count().as("total")));
}
/**
* 优化 COUNT 查询语句。
*/
public static QueryWrapper optimizeCountQueryWrapper(QueryWrapper queryWrapper, List<QueryColumn> customCountColumns) {
// 对克隆对象进行操作，不影响原来的 QueryWrapper 对象
QueryWrapper clone = queryWrapper.clone();
List<UnionWrapper> unions = CPI.getUnions(clone);
if(!CollectionUtil.isEmpty(unions)){
List<UnionWrapper> newUnions = new ArrayList<>(unions.size());
for (UnionWrapper union : unions) {
QueryWrapper unionQuery = optimizeCountQueryWrapper(union.getQueryWrapper().clone(),null);
UnionWrapper clone1 = union.clone();
clone1.setQueryWrapper(unionQuery);
newUnions.add(clone1);
}
CPI.setUnions(clone, newUnions);
}
// 将最后面的 order by 移除掉
CPI.setOrderBys(clone, null);
// 获取查询列和分组列，用于判断是否进行优化
@ -91,14 +108,20 @@ public class MapperUtil {
// 如果有 distinct、group by、having 等语句则不优化
// 这种一旦优化了就会造成 count 语句查询出来的值不对
if (hasDistinct(selectColumns) || hasGroupBy(groupByColumns) || havingCondition != null) {
return rawCountQueryWrapper(clone);
return clone;
}
// 判断能不能清除 join 语句
if (canClearJoins(clone)) {
CPI.setJoins(clone, null);
}
// 将 select 里面的列换成 COUNT(*) AS `total`
CPI.setSelectColumns(clone, Collections.singletonList(count().as("total")));
if(customCountColumns!=null){
if(hasUnion(clone)){
return rawCountQueryWrapper(clone,customCountColumns);
}else {
CPI.setSelectColumns(clone, customCountColumns);
}
}
return clone;
}
@ -118,6 +141,10 @@ public class MapperUtil {
return CollectionUtil.isNotEmpty(groupByColumns);
}
private static boolean hasUnion(QueryWrapper countQueryWrapper) {
return CollectionUtil.isNotEmpty(CPI.getUnions(countQueryWrapper));
}
private static boolean canClearJoins(QueryWrapper queryWrapper) {
List<Join> joins = CPI.getJoins(queryWrapper);
if (CollectionUtil.isEmpty(joins)) {

77
mybatis-flex-test/mybatis-flex-spring-boot-test/src/test/java/com/mybatisflex/test/common/MapperUtilTest.java
View File

@ -45,4 +45,81 @@ class MapperUtilTest {
System.out.println(MapperUtil.optimizeCountQueryWrapper(queryWrapper).toSQL());
}
/**
* 测试 (sql1) union (sql2)
*/
@Test
void testOptimizeCountQueryWrapperOfUnion1() {
//简单union
//SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_id` = 1 order by user_id desc
QueryWrapper union1 = QueryWrapper.create().select(USER.USER_ID, USER.USER_NAME).from(USER).where(USER.USER_ID.eq(1)).orderBy(USER.USER_ID.desc());
//SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_name` LIKE '%test%'
QueryWrapper union2 = QueryWrapper.create().select(USER.USER_ID, USER.USER_NAME).from(USER).where(USER.USER_NAME.like("test"));
QueryWrapper query1 = union1.union(union2);
String sql = MapperUtil.optimizeCountQueryWrapper(query1).toSQL();
//SELECT COUNT(*) AS `total` FROM ((SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_id` = 1) UNION (SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_name` LIKE '%test%')) AS `t`
System.out.println(sql);
}
/**
* 测试 (sql1 ) union (sql2 with group by)
*/
@Test
void testOptimizeCountQueryWrapperOfUnion2() {
//with group by union
//SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_id` = 1 order by user_id desc
QueryWrapper union1 = QueryWrapper.create().select(USER.USER_ID, USER.USER_NAME).from(USER).where(USER.USER_ID.eq(1)).orderBy(USER.USER_ID.desc());
//SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_name` LIKE '%test%' group by user_id, user_name
QueryWrapper union2 = QueryWrapper.create().select(USER.USER_ID, USER.USER_NAME).from(USER).where(USER.USER_NAME.like("test")).groupBy(USER.USER_ID, USER.USER_NAME);
QueryWrapper query1 = union1.union(union2);
//SELECT COUNT(*) AS `total` FROM ((SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_id` = 1) UNION (SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_name` LIKE '%test%' GROUP BY `user_id`, `user_name`)) AS `t`
String sql = MapperUtil.optimizeCountQueryWrapper(query1).toSQL();
System.out.println(sql);
}
/**
* 测试 (sql1) union (sql2 union sql3)
*/
@Test
void testOptimizeCountQueryWrapperOfUnion3() {
//with sub query union
//SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_id` = 1 order by user_id desc
QueryWrapper union1 = QueryWrapper.create().select(USER.USER_ID, USER.USER_NAME).from(USER).where(USER.USER_ID.eq(1)).orderBy(USER.USER_ID.desc());
//SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_name` LIKE '%test%' group by user_id, user_name
QueryWrapper union2 = QueryWrapper.create().select(USER.USER_ID, USER.USER_NAME).from(USER).where(USER.USER_NAME.like("test")).orderBy(USER.USER_NAME.desc());
QueryWrapper union3 = QueryWrapper.create().select(USER.USER_ID, USER.USER_NAME).from(USER).where(USER.PASSWORD.isNull()).orderBy(USER.USER_NAME.desc());
QueryWrapper query1 = union1.union(union2.union(union3));
//SELECT COUNT(*) AS `total` FROM ((SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_id` = 1) UNION ((SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_name` LIKE '%test%') UNION (SELECT `user_id`, `user_name` FROM `tb_user` WHERE `password` IS NULL ))) AS `t`
String sql = MapperUtil.optimizeCountQueryWrapper(query1).toSQL();
System.out.println(sql);
}
@Test
void testOptimizeCountQueryWrapperOfUnion4() {
//with sub query union
//SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_id` = 1 order by user_id desc
QueryWrapper union1 = QueryWrapper.create().select(USER.USER_ID, USER.USER_NAME).from(USER).where(USER.USER_ID.eq(1)).orderBy(USER.USER_ID.desc());
//SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_name` LIKE '%test%' group by user_id, user_name
QueryWrapper union2 = QueryWrapper.create().select(USER.USER_ID, USER.USER_NAME).from(USER).where(USER.USER_NAME.like("test")).orderBy(USER.USER_NAME.desc());
QueryWrapper union3 = QueryWrapper.create().from(union2).as("a");
QueryWrapper query1 = union1.union(union3);
//SELECT COUNT(*) AS `total` FROM ((SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_id` = 1) UNION ((SELECT `user_id`, `user_name` FROM `tb_user` WHERE `user_name` LIKE '%test%') UNION (SELECT `user_id`, `user_name` FROM `tb_user` WHERE `password` IS NULL ))) AS `t`
String sql = MapperUtil.optimizeCountQueryWrapper(query1).toSQL();
System.out.println(sql);
}
}