feat: Enhance MasterDetailExcelService with table alias for JOIN operations

- Added a new property `tableAlias` to distinguish between master ("m") and detail ("d") tables during JOIN operations.
- Updated the SELECT clause to include the appropriate table alias for master and detail tables.
- Improved the entity join clause construction to utilize the new table alias, ensuring clarity in SQL queries.

backend-node/src/services/masterDetailExcelService.ts

@@ -310,6 +310,7 @@ class MasterDetailExcelService {
         sourceColumn: string;
         alias: string;
         displayColumn: string;
+        tableAlias: string; // "m" (마스터) 또는 "d" (디테일) - JOIN 시 소스 테이블 구분
       }> = [];
 
       // SELECT 절 구성
@@ -332,6 +333,7 @@ class MasterDetailExcelService {
               sourceColumn: fkColumn.sourceColumn,
               alias,
               displayColumn,
+              tableAlias: "m", // 마스터 테이블에서 조인
             });
             selectParts.push(`${alias}."${displayColumn}" AS "${col.name}"`);
           } else {
@@ -360,6 +362,7 @@ class MasterDetailExcelService {
               sourceColumn: fkColumn.sourceColumn,
               alias,
               displayColumn,
+              tableAlias: "d", // 디테일 테이블에서 조인
             });
             selectParts.push(`${alias}."${displayColumn}" AS "${col.name}"`);
           } else {
@@ -373,9 +376,9 @@ class MasterDetailExcelService {
 
       const selectClause = selectParts.join(", ");
 
-      // 엔티티 조인 절 구성
+      // 엔티티 조인 절 구성 (마스터/디테일 테이블 alias 구분)
       const entityJoinClauses = entityJoins.map(ej => 
-        `LEFT JOIN "${ej.refTable}" ${ej.alias} ON m."${ej.sourceColumn}" = ${ej.alias}."${ej.refColumn}"`
+        `LEFT JOIN "${ej.refTable}" ${ej.alias} ON ${ej.tableAlias}."${ej.sourceColumn}" = ${ej.alias}."${ej.refColumn}"`
       ).join("\n        ");
 
       // WHERE 절 구성