Counting occurrences of a value in a column of a table - postgresql

Question

I have a table with multiple columns:

table1 | column1 | column2 | column3 |
       |    x    |  ....   |   ....  |
       |    y    |  ....   |   ....  |
       |    x    |  ....   |   ....  |

How can I count the occurences of a value, for example x, in one of the columns, for example column1? Given table1 this would have to return me 2 (numbers of x present in column1).

Answer 1

You can use SUM() aggregate function with a CASE statement like

select sum(case when column1 = 'x' then 1 else 0 end) as X_Count
from tabl1;

Answer 2

SELECT COUNT(*) FROM table1 WHERE column1 = 'x'