PG: be more restrictive when deducing non-nullability of columns in S…

…QL result layers (fixes #1734)
OSGeo · Jul 22, 2019 · e9bc15d · e9bc15d
1 parent ade6de9
commit e9bc15d
Showing 1 changed file with 7 additions and 1 deletion.
diff --git a/gdal/ogr/ogrsf_frmts/pg/ogrpgresultlayer.cpp b/gdal/ogr/ogrsf_frmts/pg/ogrpgresultlayer.cpp
@@ -86,7 +86,13 @@ OGRPGResultLayer::OGRPGResultLayer( OGRPGDataSource *poDSIn,
         }
     }
 
-    if( !osRequest.empty() )
+    CPLString osQuery(pszRawQueryIn);
+    // Only a INNER JOIN can guarantee that the non-nullability of source columns
+    // will be valid for the result of the join.
+    if( !osRequest.empty() &&
+        osQuery.ifind("LEFT JOIN") == std::string::npos &&
+        osQuery.ifind("RIGHT JOIN") == std::string::npos &&
+        osQuery.ifind("OUTER JOIN") == std::string::npos )
     {
         osRequest = "SELECT attnum, attrelid FROM pg_attribute WHERE attnotnull = 't' AND (" + osRequest + ")";
         PGresult* hResult = OGRPG_PQexec(poDS->GetPGConn(), osRequest );