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refactor: 重构 selectCountByQuery 方法。

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This commit is contained in:
Suomm 2023-07-04 16:37:33 +08:00
parent 6ee7dbb5ef
commit 3a82710e22
1 changed files with 19 additions and 5 deletions
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24
mybatis-flex-core/src/main/java/com/mybatisflex/core/BaseMapper.java
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@ -20,10 +20,7 @@ import com.mybatisflex.core.field.FieldQueryBuilder;
import com.mybatisflex.core.mybatis.MappedStatementTypes;
import com.mybatisflex.core.paginate.Page;
import com.mybatisflex.core.provider.EntitySqlProvider;
import com.mybatisflex.core.query.CPI;
import com.mybatisflex.core.query.QueryColumn;
import com.mybatisflex.core.query.QueryCondition;
import com.mybatisflex.core.query.QueryWrapper;
import com.mybatisflex.core.query.*;
import com.mybatisflex.core.table.TableInfo;
import com.mybatisflex.core.table.TableInfoFactory;
import com.mybatisflex.core.util.*;
@ -641,10 +638,27 @@ public interface BaseMapper<T> {
default long selectCountByQuery(QueryWrapper queryWrapper) {
List<QueryColumn> selectColumns = CPI.getSelectColumns(queryWrapper);
try {
List<Object> objects;
if (CollectionUtil.isEmpty(selectColumns)) {
// 未设置 COUNT(...) 列，默认使用 COUNT(*) 查询
queryWrapper.select(count());
objects = selectObjectListByQuery(queryWrapper);
} else if (selectColumns.get(0) instanceof CountQueryColumn) {
// 自定义 COUNT 函数，COUNT 函数必须在第一列
// 可以使用 COUNT(1)、COUNT(列名) 代替默认的 COUNT(*)
objects = selectObjectListByQuery(queryWrapper);
} else {
// 查询列中的第一列不是 COUNT 函数
if (MapperUtil.hasDistinct(selectColumns)) {
// 查询列中包含 DISTINCT 去重
// 使用子查询 SELECT COUNT(*) FROM (SELECT DISTINCT ...) AS `t`
objects = selectObjectListByQuery(MapperUtil.rawCountQueryWrapper(queryWrapper));
} else {
// 使用 COUNT(*) 替换所有的查询列
queryWrapper.select(count());
objects = selectObjectListByQuery(queryWrapper);
}
}
List<Object> objects = selectObjectListByQuery(queryWrapper);
return MapperUtil.getLongNumber(objects);
} finally {
//fixed https://github.com/mybatis-flex/mybatis-flex/issues/49