diff --git a/src/data/data-sources/sqlite/sqlite-instrument_model-data-source.ts b/src/data/data-sources/sqlite/sqlite-instrument_model-data-source.ts
index 4b76e54..452cf88 100644
--- a/src/data/data-sources/sqlite/sqlite-instrument_model-data-source.ts
+++ b/src/data/data-sources/sqlite/sqlite-instrument_model-data-source.ts
@@ -37,7 +37,7 @@ export class SQLiteInstrumentModelDataSource implements InstrumentModelDataSourc
     async create(instrument_model: InstrumentModelRequestCreationModel): Promise<number> {
         const params = [instrument_model.instrument_model_name, instrument_model.bodc_url];
         const placeholders = params.map(() => '(?)').join(','); // TODO create tool funct
-        const sql = `INSERT INTO instrument_model (instrument_model, bodc_url) VALUES (` + placeholders + `);`;
+        const sql = `INSERT INTO instrument_model (instrument_model_name, bodc_url) VALUES (` + placeholders + `);`;
 
         return await new Promise((resolve, reject) => {
             this.db.run(sql, params, function (err) {
@@ -79,7 +79,7 @@ export class SQLiteInstrumentModelDataSource implements InstrumentModelDataSourc
                     filtering_sql += filter.field + ` = 0`;
                 }
                 // If value is undefined, null or empty, and operator =, set to is null
-                else if (filter.value == undefined || filter.value == null || filter.value == "") {
+                else if (filter.value == "null") {
                     if (filter.operator == "=") {
                         filtering_sql += filter.field + ` IS NULL`;
                     } else if (filter.operator == "!=") {
diff --git a/src/data/data-sources/sqlite/sqlite-privilege-data-source.ts b/src/data/data-sources/sqlite/sqlite-privilege-data-source.ts
index fb499cf..4988c69 100644
--- a/src/data/data-sources/sqlite/sqlite-privilege-data-source.ts
+++ b/src/data/data-sources/sqlite/sqlite-privilege-data-source.ts
@@ -130,7 +130,7 @@ export class SQLitePrivilegeDataSource implements PrivilegeDataSource {
                     filtering_sql += "privilege." + filter.field + ` = 0`;
                 }
                 // If value is undefined, null or empty, and operator =, set to is null
-                else if (filter.value == undefined || filter.value == null || filter.value == "") {
+                else if (filter.value == "null") {
                     if (filter.operator == "=") {
                         filtering_sql += "privilege." + filter.field + ` IS NULL`;
                     } else if (filter.operator == "!=") {
@@ -216,7 +216,7 @@ export class SQLitePrivilegeDataSource implements PrivilegeDataSource {
         // remove last AND
         placeholders = placeholders.slice(0, -4);
         // form final sql
-        const sql = `SELECT privilege.*, user.first_name, user.last_name, user.email, FROM privilege LEFT JOIN user ON privilege.user_id = user.user_id WHERE ` + placeholders + `LIMIT 1;`;
+        const sql = `SELECT privilege.*, user.first_name, user.last_name, user.email FROM privilege LEFT JOIN user ON privilege.user_id = user.user_id WHERE ` + placeholders + `LIMIT 1;`;
         return await new Promise((resolve, reject) => {
             this.db.get(sql, params, (err, row) => {
                 if (err) {
diff --git a/src/data/data-sources/sqlite/sqlite-project-data-source.ts b/src/data/data-sources/sqlite/sqlite-project-data-source.ts
index e62dcfb..326cfe3 100644
--- a/src/data/data-sources/sqlite/sqlite-project-data-source.ts
+++ b/src/data/data-sources/sqlite/sqlite-project-data-source.ts
@@ -166,7 +166,7 @@ export class SQLiteProjectDataSource implements ProjectDataSource {
                     filtering_sql += filter.field + ` = 0`;
                 }
                 // If value is undefined, null or empty, and operator =, set to is null
-                else if (filter.value == undefined || filter.value == null || filter.value == "") {
+                else if (filter.value == "null") {
                     if (filter.operator == "=") {
                         filtering_sql += filter.field + ` IS NULL`;
                     } else if (filter.operator == "!=") {
diff --git a/src/data/data-sources/sqlite/sqlite-user-data-source.ts b/src/data/data-sources/sqlite/sqlite-user-data-source.ts
index a38354a..14fe5c5 100644
--- a/src/data/data-sources/sqlite/sqlite-user-data-source.ts
+++ b/src/data/data-sources/sqlite/sqlite-user-data-source.ts
@@ -82,7 +82,7 @@ export class SQLiteUserDataSource implements UserDataSource {
                     filtering_sql += filter.field + ` = 0`;
                 }
                 // If value is undefined, null or empty, and operator =, set to is null
-                else if (filter.value == undefined || filter.value == null || filter.value == "") {
+                else if (filter.value == "null") {
                     if (filter.operator == "=") {
                         filtering_sql += filter.field + ` IS NULL`;
                     } else if (filter.operator == "!=") {