sql - MySQL SELECT only not null values - Stack Overflow Is it possible to do a select statement that takes only NOT NULL values? Right now I am using this: SELECT * FROM table And then I have to filter out the null values with a php loop Is there a
sql - How to do a Select in a Select - Stack Overflow I have a table containing a unique ID field Another field (REF) contains a reference to another dataset's ID field Now I have to select all datasets where REF points to a dataset that doesn't exi
mysql - SELECT * WHERE NOT EXISTS - Stack Overflow SELECT * from employees WHERE NOT EXISTS ( SELECT name FROM eotm_dyn WHERE eotm_dyn employeeid = employees employeeid ) assuming that the two tables are linked by a foreign key relationship At this point you could use a variety of other options including a LEFT JOIN The optimizer will typically handle them the same in most cases, however
How to select unique records by SQL - Stack Overflow When I perform SELECT * FROM table I got results like below: 1 item1 data1 2 item1 data2 3 item2 data3 4 item3 data4 As you can see, there are dup records from column2 (item1 are dupped) So how co
sql - select * vs select column - Stack Overflow If I just need 2 3 columns and I query SELECT * instead of providing those columns in select query, is there any performance degradation regarding more less I O or memory? The network overhead mig