postgresql - simple postgres syntax issue -

I am new to postgres from SQL Server. I have written a function getSkill which takes an integer and from the "Skills" table. One type of "skill", now I want to feed the "integer" type integer from the "jobs" table. If I do this, the posters say that the syntax is error and ^ returns. Scott puts a little caret on. Choose "Select" from GetSkill (Select "SkidID" from "Jobs", where "Job ID" = "PosID") // Syntax Error ^ ^ getSkill

I'm pretty sure that () A statement is a postgres statement - but if I change it with an integer syntax error it moves away. By getting GetSkill ("0") //,

  selects an error saying that there is no line at position 0 in the DB, because it is still not complete   
 This is misleading to me syntax error if I return an integer with a valid integer seems to take place to replace a valid postres statement.  
 Can anyone tell what is happening?   
 
 
 I think it should be  
  GetSkill from jobs ( SkillID), where JobID = "posID"