从表B中选择数据，表B中的字段与表A（php mySQL）匹配

Question

I have a table which contains a list of livestock ("livestock"), this gets regularly updated and changed. I also have a second table ("description") containing two columns "Scientific" and "Description".

I need to select the Description field from the description table when the Scientific field in both tables matches but not sure how best to do this.

Hope this makes sense, any help is much appreciated

Answer 1

Since you have mismatches between two of your tables (meaning not all rows in livestock have respective rows in description) you most likely have to use an OUTER JOIN (LEFT or RIGHT) to achieve your goal

SELECT l.*, d.description
  FROM livestock l LEFT JOIN description d
    ON l.scientific = d.scientific

Here is SQLFiddle demo

Further reading

• A Visual Explanation of SQL Joins

On a side note: When asking query related questions, especially when you don't provide your version of the query, please at least help those who want to help you and provide your table(s) schema, sample data, and desired output based on it. Better yet spend one minute and create sqlfiddle with your sample data.