How to include three geometries in one query - PostGIS

I am new to SQL and I am having difficulty creating a query which includes three geometries. I have a point layer (building) from which I want to count all the points-buildings that they have a maximum distance of 50 meters from the lines (roads) in a certain polygon (municipal unit) using some extra criteria for the two out of three tables.

Here's the table structure:

Table 1: building (id_building, address_name,color_tagged,point)
Table 2: roads (id_road, line) 
Table 3: munic_units (id_munic, munic_name, polygon)

I tried the code below and I have made a lot of changes..but it gives me errors. I would be glad to hear any suggestions. Thank you.

SELECT address_name, count(*) AS Frequency,munic_name,color_tagged
FROM building,roads,munic_units 
WHERE ST_CONTAINS((SELECT polygon FROM munic_units WHERE munic_name=''),(ST_DWithin((SELECT point FROM building WHERE color_tagged=''),line,50))) 
GROUP BY address_name,munic_name,color_tagged 
ORDER BY Frequency DESC,address_name DESC;

First, I tried a simpler version with two geometries:

SELECT address_name, count(*) AS Frequency,color_tagged
FROM building,roads,loc_munic_units
WHERE ST_Dwithin(point,roads_geom,50) AND color_tagged='YELLOW'
GROUP BY address_name,color_tagged
ORDER BY Frequency DESC,address_name DESC;

and returns...enter image description here ..the expected result in this stage was to find all the buildings in a distance of 50 meters from roads which have color_tagged as 'Yellow'. The final desired result is to run the previous search only in a specific area - one polygon.The structure of tables is as showed below.

Solution

You are close to the solution. The 1st query fails because you are not properly joining the tables. The 2nd query likely returns over-estimated counts because you do a cross join with the city table.

Using the 2nd query, you can add the missing join condition (and properly write the joins)

SELECT address_name, count(*) AS Frequency,color_tagged
FROM building b  --selects from buildings
 JOIN roads r ON ST_Dwithin(b.point,r.roads_geom,50) -- when building is within 50 of a road
 JOIN loc_munic_units m ON ST_WITHIN(r.roads_geom, m.polygon) -- and when the road is within a municipality polygon
WHERE b.color_tagged='YELLOW' AND m.munic_name = 'abc' -- restrain to a specific municipality (or >1) and color
GROUP BY address_name,color_tagged
ORDER BY Frequency DESC,address_name DESC;