大约有 40,000 项符合查询结果（耗时：0.0281秒） [XML]
SQL server query to get the list of columns in a table along with Data types, NOT NULL, and PRIMARY
...licate rows for some columns, use user_type_id instead of system_type_id.
SELECT
c.name 'Column Name',
t.Name 'Data type',
c.max_length 'Max Length',
c.precision ,
c.scale ,
c.is_nullable,
ISNULL(i.is_primary_key, 0) 'Primary Key'
FROM
sys.columns c
INNER JOIN
...
SQL JOIN - WHERE clause vs. ON clause
...
They are not the same thing.
Consider these queries:
SELECT *
FROM Orders
LEFT JOIN OrderLines ON OrderLines.OrderID=Orders.ID
WHERE Orders.ID = 12345
and
SELECT *
FROM Orders
LEFT JOIN OrderLines ON OrderLines.OrderID=Orders.ID
AND Orders.ID = 12345
The first will re...
Using psql how do I list extensions installed in a database?
...org/docs/current/static/app-psql.html
Doing it in plain SQL it would be a select on pg_extension:
SELECT *
FROM pg_extension
http://www.postgresql.org/docs/current/static/catalog-pg-extension.html
share
|
...
configure: error: C compiler cannot create executables
...'ve installed Xcode 4.3.x, you need to launch it, go into its preferences, select the Downloads tab, and click "Install" next to the Command Line Tools package.
share
|
improve this answer
...
Max return value if empty query
...oeSize = Workers.Where(x => x.CompanyId == 8)
.Select(x => x.ShoeSize)
.DefaultIfEmpty(0)
.Max();
The zero in DefaultIfEmpty is not necessary.
...
How do I temporarily disable triggers in PostgreSQL?
...ct = 'disable';
else
act = 'enable';
end if;
for r in select c.relname from pg_namespace n
join pg_class c on c.relnamespace = n.oid and c.relhastriggers = true
where n.nspname = nsp
loop
execute format('alter table %I %s trigger all', r.relname, act)...
How to resume Fragment from BackStack if exists
...teName);
ft.commit();
}
}
The conditional was changed a bit since selecting the same fragment while it was visible also caused duplicate entries.
Implementation:
I highly suggest not taking the the updated replaceFragment() method apart like you did in your code. All the logic is containe...
SQL is null and = null [duplicate]
...e t (x int, y int);
insert into t values (null, null), (null, 1), (1, 1);
select 'x = null' as test , x, y from t where x = null
union all
select 'x != null', x, y from t where x != null
union all
select 'not (x = null)', x, y from t where not (x = null)
union all
select 'x = y', x, y from t where ...
How do I remedy “The breakpoint will not currently be hit. No symbols have been loaded for this docu
...ocess. Locate the one you want to get debug info for. Right-click it and select Symbol Load Information. You'll get a dialog that lists all the directories where it looked for the .pdb file for the assembly. Verify that list against the actual .pdb location. Make sure it doesn't find an old one...
What's the false operator in C# good for?
...he operator false declared in T, and T.&(x, y) is an invocation of the selected operator &. In other words, x is first evaluated and operator false is invoked on the result to determine if x is definitely false. Then, if x is definitely false, the result of the operation is the value previou...