Question

I am new to SQL and relational DBMS. I want to retrieve records from a relational database if they satisfy 3 given properties.

For example, if there is a table containing info about solids:

table_solid : |s_id|s_name|description| table_width : |w_id|w_name| table_height: |h_id|h_name| table_length: |l_id|l_name| 

where *_id are all primary keys.

I have 3 more tables for relating these tables with Foreign Keys.

table_s_h: |s_id|h_id| table_s_w: |s_id|w_id| table_s_l: |s_id|l_id| 

Would you please explain how do I join these.

Thanks in advance.

                 --------- table_length table_SOLID ----                 ----------- table_width                  ------------table_height 

table_length contains valid lengths that solid can take (and similarly with other tables).

Answer 1

From a single table:

Select *  FROM TABLE_NAME WHERE table_width = SOME_VALUE3 AND table_height= SOME_VALUE2 AND table_length = SOME_VALUE3 

Is that what you are looking for? Or are you trying to query multiple tables? If so try this:

Select *  FROM TABLE_SOLID solid Inner join table_width width on solid.w_id = width.w_id inner join table_height height on solid.h_id = height.h_id inner join table_length length on solid.l_id = length.l_id 

This link may be of use to you http://dev.mysql.com/doc/refman/5.0/en/join.html