> For the complete documentation index, see [llms.txt](https://olivers-expression-lab.gitbook.io/filter-expressions-in-fme/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://olivers-expression-lab.gitbook.io/filter-expressions-in-fme/logical-operators.md). # Logical Operators In previous chapters we learned how to do different attributive and spatial queries. Let's combine them by using Logical Operators. ## OR Let's start with the **OR-Operator** (logical disjunction). We will use the parking decks-WFS provided by Hanseatic City of Hamburg we already used in [Comparison Operators](/filter-expressions-in-fme/comparison-operators.md). | Parameter | Value | | -------------- | ------------------------------------------------------------------------------------------------------------ | | WFS URL | | | Version | 2.0.0 | | Features Types | verkehr\_parkhaeuser | | Max Features | leave blank | | xmlns | de.hh.up="" | | |

preise (de) = fees (en)
kostenlos (de) = free of charge (en)
keine Gebühr (de) = no charge (en)

| The services provides an attribute called "preise", i.e. fees. First, we will look for all parking decks, which can be used free of charge (**kostenlos**), at least for some time (half an hour or an hour). The word "kostenlos" occurs in different mixtures like * 1\. Stunde **kostenlos**|2. Stunde 1,20 EUR | jede weitere Std. 1,50 EUR|Tageshöchstsatz k. A. * 1\. Stunde **kostenlos**|jede weitere Std. 1,50 EUR|Tageshöchstsatz 15,00 EUR * halbe Stunde: **kostenlos**|2. halbe Stunde: 0,50 EUR|2. Stunde: 1,00 EUR| (...) Remember what we learned in [Comparison Operators](/filter-expressions-in-fme/comparison-operators.md) about **Wildcards** using the **PropertyIsLike**-Operator. ```xml de.hh.up:preise *kostenlos* ``` Using this filter expression, the service will return **5** features (at the time of publication of this chapter): * 10047 Elbe Einkaufszentrum (EEZ) * 10076 Alstertal Einkaufszentrum (AEZ) Ost * 10094 Harburg Carree * 10116 Alstertal Einkaufszentrum (AEZ) Mitte * 10117 Alstertal Einkaufszentrum (AEZ) West Next, we will look for all parking decks with no charges (**keine Gebühren**) using the well-known **PropertyIsEqualTo**-Operator. ```xml de.hh.up:preise keine Gebühren ``` The WFS will return **3** additional features: * 10089 Sander Markt * 10090 Frascatiplatz * 10091 Lohbrügger Marktplatz Instead of sending two separate (disjoined) requests, we can combine them into one single request using the OR-Operator as shown below: ```xml de.hh.up:preise *kostenlos* de.hh.up:preise keine Gebühren ``` The only simple trick is to **embrace your expressions** (to be precise, the conditions within the expression) **by the logical operator** needed, i.e. ``` OR CONDITION 1 CONDITION 2 ... /OR ``` ``` AND CONDITION 1 CONDITION 2 ... /AND ``` If you're a programmer, this may be unfamiliar for you because you normally connect conditions by logical operators like this: ``` CONDITION 1 OR CONDITION 2 OR CONDITION 3 ``` So please keep in mind: logical operators embrace conditions within filter expressions. ## AND Recapitulating what we have learned, using other logical operators is really easy: * take two or more filter expressions * make sure, that they are working stand-alone (please test them!) * combine them by enclosing them by logical operators To do so, we will have a look at the **AND-Operator** (logical conjunction) using a mining-WFS provided by Federal State of Brandenburg. | Parameter | Value | | -------------- | ---------------------------------------------------------------------------------------------------------- | | WFS URL | (mining) | | Version | 2.0 | | Features Types | bgberechtig (mining rights) | | Max Features | leave blank | | xmlns |

fes=""
app=""

| | |

inhaber (de) = holder (en)
bodenschatz\_kurz (de) = resource, abbr. (en)
Ton (de) = clay (en)

| First, we want to get all mining rights in Brandenburg owned by the company called "BVVG Bodenverwertungs- und -verwaltungs GmbH". ```xml app:inhaber BVVG Bodenverwertungs- und -verwaltungs GmbH ``` The WFS will return 35 polygon features. Next, we're interested in all clay pits. ```xml app:bodenschatz_kurz Ton ``` We will get 29 polygon features. If we want to see only the clay pits owned by BVVG, we have to put all of this together using the **AND-Operator**. ```xml app:inhaber BVVG Bodenverwertungs- und -verwaltungs GmbH app:bodenschatz_kurz Ton ``` The WFS will return 7 polygon features. ## Good to know #4 You may ask yourself: is it possible to combine both 1. Comparison Operators 2. Spatial Operators ??? The answer is: yes, it is possible! To demonstrate it, just copy the **BBOX-Expression** from [Spatial Operators](/filter-expressions-in-fme/spatial-operators.md#bbox) ```xml 367441.62 5620100.532 367619.15 5620254.767 ``` Next, create a **PropertyIsLike-Expression** like this ```xml cp:nationalCadastralReference 054302026* ``` Check, if both expressions are running stand-alone. If so, please combine them using the **AND-Operator**: ```xml cp:nationalCadastralReference 054302026* 367441.62 5620100.532 367619.15 5620254.767 ``` What's the difference? See for yourself!