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    <p>You could <a href="http://www.codinghorror.com/blog/2007/10/a-visual-explanation-of-sql-joins.html" rel="nofollow">join</a> <code>Table2</code> to <code>Table1</code> multiple times, once for each column:</p> <pre><code>SELECT Table1.id, Table1.name, Table2_t1.cname AS t1cname, Table2_t1.cname AS t2cname, Table2_L1.cname AS L1cname, Table2_L2.cname AS L2cname, Table2_L3.cname AS L3cname, Table2_L4.cname AS L4cname, Table2_L5.cname AS L5cname, Table2_L6.cname AS L6cname, Table2_L7.cname AS L7cname, Table2_L8.cname AS L8cname, Table2_L9.cname AS L9cname, Table2_L10.cname AS L10cname FROM Table1 JOIN Table2 AS Table2_t1 ON Table2_t1.cid = Table1.t1cid JOIN Table2 AS Table2_t2 ON Table2_t2.cid = Table1.t2cid JOIN Table2 AS Table2_L1 ON Table2_L1.cid = Table1.L1cid JOIN Table2 AS Table2_L2 ON Table2_L2.cid = Table1.L2cid JOIN Table2 AS Table2_L3 ON Table2_L3.cid = Table1.L3cid JOIN Table2 AS Table2_L4 ON Table2_L4.cid = Table1.L4cid JOIN Table2 AS Table2_L5 ON Table2_L5.cid = Table1.L5cid JOIN Table2 AS Table2_L6 ON Table2_L6.cid = Table1.L6cid JOIN Table2 AS Table2_L7 ON Table2_L7.cid = Table1.L7cid JOIN Table2 AS Table2_L8 ON Table2_L8.cid = Table1.L8cid JOIN Table2 AS Table2_L9 ON Table2_L9.cid = Table1.L9cid JOIN Table2 AS Table2_L10 ON Table2_L10.cid = Table1.L10cid WHERE Table1.active = 1 </code></pre> <p>Or, alternatively, you could join the tables once and then group the results:</p> <pre><code>SELECT Table1.id, Table1.name, MAX(IF(Table1.t1cid =Table2.cid, Table2.cname, NULL)) AS t1cname, MAX(IF(Table1.t2cid =Table2.cid, Table2.cname, NULL)) AS t2cname, MAX(IF(Table1.L1cid =Table2.cid, Table2.cname, NULL)) AS L1cname, MAX(IF(Table1.L2cid =Table2.cid, Table2.cname, NULL)) AS L2cname, MAX(IF(Table1.L3cid =Table2.cid, Table2.cname, NULL)) AS L3cname, MAX(IF(Table1.L4cid =Table2.cid, Table2.cname, NULL)) AS L4cname, MAX(IF(Table1.L5cid =Table2.cid, Table2.cname, NULL)) AS L5cname, MAX(IF(Table1.L6cid =Table2.cid, Table2.cname, NULL)) AS L6cname, MAX(IF(Table1.L7cid =Table2.cid, Table2.cname, NULL)) AS L7cname, MAX(IF(Table1.L8cid =Table2.cid, Table2.cname, NULL)) AS L8cname, MAX(IF(Table1.L9cid =Table2.cid, Table2.cname, NULL)) AS L9cname, MAX(IF(Table1.L10cid=Table2.cid, Table2.cname, NULL)) AS L10cname FROM Table1 JOIN Table2 ON Table2.cid IN ( Table1.t1cid, Table1.t2cid, Table1.L1cid, Table1.L2cid, Table1.L3cid, Table1.L4cid, Table1.L5cid, Table1.L6cid, Table1.L7cid, Table1.L8cid, Table1.L9cid, Table1.L10cid ) WHERE Table1.active = 1 GROUP BY Table1.id </code></pre> <p>I think the first solution ought to be faster, especially if you have indexes on <code>Table2.cid</code> and the foreign key columns in <code>Table1</code>&mdash;but perhaps it's worth benchmarking the two approaches to see which is better?</p>
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