API/Queries/Attributes.md

@@ -172,31 +172,78 @@ Use `+columns` to get all columns of the base table plus certain ones from joine
 
 # Select and As
 
-RESTRICTIONS: keys and values may not contain spaces.
+The "select" and "as" attribues allow even more flexibility to define exactly what should be returned than "columns" does. Other than renaming a column,
+functions may be used to select calculated values.
 
-The "select" and "as" attribues allow even more flexibility to define exactly what should be returned than "columns" does.
+## Restrictions
 
-```JSON
-"attrs" : {
-    "join":   [ "contracts__working_time_constraint" ],
-    "select": [ {"min" : "max_hours_per_day"} ],
-    "as":     [ "min_max" ]
+Keys and values may not contain spaces.
+
+## Examples
+
+Only select one column and name it "me_id" from system.entity:
+
+`POST /data/system/entity/query`
+
+```json
+{
+  "attrs": {
+    "select": "me.id",
+    "as": "me_id"
+  }
+}
+```
+
+Result:
+
+```json
+{
+  "data": [
+    {
+      "me_id": 1
+    },
+    {
+      "me_id": 2
+    }
+  ]
+}
+```
+
+Select the maximum id from system.entity:
+
+`POST /data/system/entity/query`
+
+```json
+{
+  "attrs": {
+    "select": [
+      {
+        "max": "me.id"
+      }
+    ],
+    "as": [
+      "max_id"
+    ]
+  }
+}
 }
 ```
 
 Generates:
 
-```SQL
-SELECT MIN( max_hours_per_day )
-FROM contracts.collective_agreement() me
-LEFT JOIN contracts.working_time_constraint() contracts_working_time_constraint ON contracts_working_time_constraint.collective_agreement = me.id
-LIMIT 10
+```sql
+SELECT MAX( me.id ) FROM system.entity()
 ```
 
 Returns one row:
-```JSON
+
+```json
 {
-    "min_max": "9"
+  "data": [
+    {
+      "max_id": 99
+    }
+  ]
 }
 ```