Removed useless NULLIF calls (#1214)

`NULLIF(wikipedia, '') IS NOT NULL` replaced by `wikipedia <> ''`
https://stackoverflow.com/questions/23766084/best-way-to-check-for-empty-or-null-value

layers/mountain_peak/mountain_peak.sql

@@ -44,8 +44,8 @@ FROM (
                     PARTITION BY LabelGrid(geometry, 100 * pixel_width)
                     ORDER BY (
                             substring(ele FROM E'^(-?\\d+)(\\D|$)')::int +
-                            (CASE WHEN NULLIF(wikipedia, '') IS NOT NULL THEN 10000 ELSE 0 END) +
-                            (CASE WHEN NULLIF(name, '') IS NOT NULL THEN 10000 ELSE 0 END)
+                            (CASE WHEN wikipedia <> '' THEN 10000 ELSE 0 END) +
+                            (CASE WHEN name <> '' THEN 10000 ELSE 0 END)
                         ) DESC
                     )::int AS "rank"
          FROM osm_peak_point
@@ -80,8 +80,8 @@ FROM (
                 row_number() OVER (
                     PARTITION BY LabelGrid(geometry, 100 * pixel_width)
                     ORDER BY (
-                            (CASE WHEN NULLIF(wikipedia, '') IS NOT NULL THEN 10000 ELSE 0 END) +
-                            (CASE WHEN NULLIF(name, '') IS NOT NULL THEN 10000 ELSE 0 END)
+                            (CASE WHEN wikipedia <> '' THEN 10000 ELSE 0 END) +
+                            (CASE WHEN name <> '' THEN 10000 ELSE 0 END)
                         ) DESC
                     )::int AS "rank"
          FROM osm_mountain_linestring

layers/poi/poi_stop_agg.sql

@@ -5,7 +5,7 @@ SELECT uic_ref,
        count(*) AS count,
        CASE WHEN count(*) > 2 THEN ST_Centroid(ST_UNION(geometry)) END AS centroid
 FROM osm_poi_point
-WHERE nullif(uic_ref, '') IS NOT NULL
+WHERE uic_ref <> ''
   AND subclass IN ('bus_stop', 'bus_station', 'tram_stop', 'subway')
 GROUP BY uic_ref
 HAVING count(*) > 1

layers/transportation/transportation.sql

@@ -36,12 +36,12 @@ $$
 SELECT osm_id,
        geometry,
        CASE
-           WHEN NULLIF(highway, '') IS NOT NULL OR NULLIF(public_transport, '') IS NOT NULL
+           WHEN highway <> '' OR public_transport <> ''
                THEN highway_class(highway, public_transport, construction)
-           WHEN NULLIF(railway, '') IS NOT NULL THEN railway_class(railway)
-           WHEN NULLIF(aerialway, '') IS NOT NULL THEN 'aerialway'
-           WHEN NULLIF(shipway, '') IS NOT NULL THEN shipway
-           WHEN NULLIF(man_made, '') IS NOT NULL THEN man_made
+           WHEN railway <> '' THEN railway_class(railway)
+           WHEN aerialway <> '' THEN 'aerialway'
+           WHEN shipway <> '' THEN shipway
+           WHEN man_made <> '' THEN man_made
            END AS class,
        CASE
            WHEN railway IS NOT NULL THEN railway

layers/transportation_name/update_transportation_name.sql

@@ -33,7 +33,7 @@ FROM (
         slice_language_tags(hl.tags) AS tags,
         rm1.network_type,
         CASE
-            WHEN rm1.network_type IS NOT NULL AND nullif(rm1.ref::text, '') IS NOT NULL
+            WHEN rm1.network_type IS NOT NULL AND rm1.ref::text <> ''
                 THEN rm1.ref::text
             ELSE NULLIF(hl.ref, '')
             END AS ref,
@@ -58,7 +58,7 @@ FROM (
             LEFT OUTER JOIN osm_route_member rm5 ON rm5.member = hl.osm_id AND rm5.concurrency_index=5
             LEFT OUTER JOIN osm_route_member rm6 ON rm6.member = hl.osm_id AND rm6.concurrency_index=6
     WHERE (hl.name <> '' OR hl.ref <> '' OR rm1.ref <> '' OR rm1.network <> '')
-      AND NULLIF(hl.highway, '') IS NOT NULL
+      AND hl.highway <> ''
 ) AS t;
 CREATE INDEX IF NOT EXISTS osm_transportation_name_network_osm_id_idx ON osm_transportation_name_network (osm_id);
 CREATE INDEX IF NOT EXISTS osm_transportation_name_network_name_ref_idx ON osm_transportation_name_network (coalesce(name, ''), coalesce(ref, ''));
@@ -338,7 +338,7 @@ BEGIN
             slice_language_tags(hl.tags) AS tags,
             rm.network_type,
             CASE
-                WHEN rm1.network_type IS NOT NULL AND nullif(rm1.ref::text, '') IS NOT NULL
+                WHEN rm1.network_type IS NOT NULL AND rm1.ref::text <> ''
                     THEN rm1.ref::text
                 ELSE NULLIF(hl.ref, '')
                 END AS ref,
@@ -355,7 +355,7 @@ BEGIN
             hl.osm_id = c.osm_id
                 LEFT OUTER JOIN osm_route_member rm ON rm.member = hl.osm_id AND rm.concurrency_index=1
         WHERE (hl.name <> '' OR hl.ref <> '')
-          AND NULLIF(hl.highway, '') IS NOT NULL
+          AND hl.highway <> ''
     ) AS t;
 
     -- noinspection SqlWithoutWhere