MySQL “CREATE TABLE IF NOT EXISTS” -> Error 1050
Works fine for me in 5.0.27 I just get a warning (not an error) that the table exists;
SQL
When should I use CROSS APPLY over INNER JOIN?
Can anyone give me a good example of when CROSS APPLY makes a difference in those cases where INNER JOIN will work as well? See the article in my blog for detailed performance comparison: INNER JOIN vs. CROSS APPLY CROSS APPLY works better on things that have no simple JOIN condition. This one selects 3 … Read more
Conversion failed when converting date and/or time from character string while inserting datetime
There are many formats supported by SQL Server – see the MSDN Books Online on CAST and CONVERT. Most of those formats are dependent on what settings you have – therefore, these settings might work some times – and sometimes not. The way to solve this is to use the (slightly adapted) ISO-8601 date format that is supported by SQL … Read more
SQL SELECT WHERE field contains words
Rather slow, but working method to include any of words: If you need all words to be present, use this: If you want something faster, you need to look into full text search, and this is very specific for each database type.
MySQL – Operand should contain 1 column(s)
Your subquery is selecting two columns, while you are using it to project one column (as part of the outer SELECT clause). You can only select one column from such a query in this context. Consider joining to the users table instead; this will give you more flexibility when selecting what columns you want from … Read more
SQL query to select dates between two dates
you should put those two dates between single quotes like.. or can use keep in mind that the first date is inclusive, but the second is exclusive, as it effectively is ‘2011/02/27 00:00:00’
how to fix oracle ORA-01722 invalid number error
If you have a numeric column, all you have to do is use a to_char with the right parameters; this should do the work:
Self Join to get employee manager name
EDIT: Left Join will work if emp_mgr_id is null.
Conversion failed when converting date and/or time from character string while inserting datetime
There are many formats supported by SQL Server – see the MSDN Books Online on CAST and CONVERT. Most of those formats are dependent on what settings you have – therefore, these settings might work some times – and sometimes not. The way to solve this is to use the (slightly adapted) ISO-8601 date format … Read more