I haven't used CHAR much in the past as I seemed to use VARCHAR too much; I'm trying to use CHAR when appropriate lately & from what I understand you use it when the data...
Then in the second table I have select ..., null as opt from... I know that I could have an empty string with '' as opt however, I don't want an empty string, I really do need it to be null.
select a,b,null,null from table1 union select null,null,c,d from table2 union select null,null,null,null,e,f from table3.
Normally it will match if id = 23 exist in both tables. But it's not the case (not in t1 table) so the request return NULL values. How i can do to return no result?
Select char_length(cast('123456789 1' as varchar(10))) from rdb$database. Получаем: Exception ... string truncation Т.е. пробел мы обрезать можем, а другие символы нет.
select cast (2000 as type of quint) from rdb$database select cast (2000 as int) from rdb$database. If TYPE OF is used with a (VAR)CHAR type, its character.
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I'm having a problem where when I try to select the rows that have a NULL for a certain column, it returns an empty set.
union all select null,null,null,null,null,null,null,null,null,null,null,null,null,null,null