title: Query works fine with only one LIKE clause, when I add another my results completely change?
body: <p>I am currently trying to create a little report on our logging, however it isn't working as I expected it to. </p>
  
  <p>I have created a query which works fine when I only have 1 LIKE clause, however when I add an OR to the query, my results get screwed up. I am not sure as to why this is happening. Am I missing grouping or something? </p>
  
  <p>Here is the query where it works:</p>
  
  <pre><code>select
  s.SupportCode
  , s.DateTaken
  , s.TakenBy
  , s.AllocatedTo
  --, p.IndustrySector
  from
  Support s
  join Project p on p.ProjectCode = s.ProjectCode
  where
  s.DateTaken &gt;= dateadd(month, datediff(month, 0, dateadd(m, -6, current_timestamp)),0)
  and s.SupportAction like '%RMC%'
  </code></pre>
  
  <p>Here is the result, which is what I want:</p>
  
  <pre><code>╔══════════╦═════════════════════════╦═════╦═════╗
  ║ 00074062 ║ 2017-01-25 00:00:00.000 ║ JCH ║ JCH ║
  ║ 00073482 ║ 2016-12-14 00:00:00.000 ║ ROA ║ FJ  ║
  ║ 00072764 ║ 2016-11-10 00:00:00.000 ║ ROA ║ ROA ║
  ║ 00072660 ║ 2016-11-03 00:00:00.000 ║ FJ  ║ FJ  ║
  ║ 00073818 ║ 2017-01-11 00:00:00.000 ║ ROA ║ FJ  ║
  ║ 00070844 ║ 2016-09-14 00:00:00.000 ║ ROA ║ FJ  ║
  ║ 00070988 ║ 2016-09-22 00:00:00.000 ║ ROA ║ ROA ║
  ╚══════════╩═════════════════════════╩═════╩═════╝
  </code></pre>
  
  <p>Here is the query when I add the other LIKE clauses:</p>
  
  <pre><code>select
  s.SupportCode
  , s.DateTaken
  , s.TakenBy
  , s.AllocatedTo
  --, p.IndustrySector
  from
  Support s
  join Project p on p.ProjectCode = s.ProjectCode
  where
  s.DateTaken &gt;= dateadd(month, datediff(month, 0, dateadd(m, -6, current_timestamp)),0)
  and s.SupportAction like '%RMC%'
   or s.SupportAction like '%FJ%'
   or s.SupportAction like '%DG%'
   or s.SupportAction like '%VIC%';
  </code></pre>
  
  <p>Here are the results:</p>
  
  <pre><code>╔══════════╦═════════════════════════╦═════╦══════╗
  ║ 00031254 ║ 1996-11-04 00:00:00.000 ║ KGB ║ KGB  ║
  ║ 00031279 ║ 1996-11-12 00:00:00.000 ║ TB  ║ TMB  ║
  ║ 00031296 ║ 1996-11-18 00:00:00.000 ║ SPB ║ BJR  ║
  ║ 00031402 ║ 1997-01-07 00:00:00.000 ║ AJS ║ AJS  ║
  ║ 00031474 ║ 1997-02-04 00:00:00.000 ║ BJR ║ NULL ║
  ║ 00031513 ║ 1997-02-19 00:00:00.000 ║ NS  ║ NULL ║
  ║ 00031538 ║ 1997-02-25 00:00:00.000 ║ SPB ║ SPB  ║
  ╚══════════╩═════════════════════════╩═════╩══════╝
  </code></pre>
  
  <p>Why is this happening? I can't think as to why.</p>
  
  <p>Any help would be appreciated.</p>