大约有 37,000 项符合查询结果（耗时：0.0365秒） [XML]
How do I spool to a CSV formatted file using SQLPLUS?
...t for numbers (avoid scientific notation on IDs)
spool myfile.csv
select table_name, tablespace_name
from all_tables
where owner = 'SYS'
and tablespace_name is not null;
Output will be like:
TABLE_PRIVILEGE_MAP ,SYSTEM
SYSTEM_PRIVILEGE_MAP ...
Select distinct values from a table field
...M. What I want to do is get a list of distinct values within a field on my table .... the equivalent of one of the following:
...
MySQL load NULL values from CSV data
... up containing an empty string:
LOAD DATA INFILE '/tmp/testdata.txt'
INTO TABLE moo
FIELDS TERMINATED BY ","
LINES TERMINATED BY "\n"
(one, two, three, @vfour, five)
SET four = NULLIF(@vfour,'')
;
If they're all possibly empty, then you'd read them all into variables and have multiple SET stateme...
Difference between partition key, composite key and clustering key in Cassandra?
...neral concept to indicate one or more columns used to retrieve data from a Table.
The primary key may be SIMPLE and even declared inline:
create table stackoverflow_simple (
key text PRIMARY KEY,
data text
);
That means that it is made by a single column.
But the primary ke...
How to align 3 divs (left/center/right) inside another div?
...ide another div.
#container {
display: flex; /* establish flex container */
flex-direction: row; /* default value; can be omitted */
flex-wrap: nowrap; /* default value; can be omitted */
justify-content: space-between; /* switched from defau...
MySQL: Large VARCHAR vs. TEXT?
I've got a messages table in MySQL which records messages between users. Apart from the typical ids and message types (all integer types) I need to save the actual message text as either VARCHAR or TEXT. I'm setting a front-end limit of 3000 characters which means the messages would never be inserte...
PostgreSQL - fetch the row which has the Max value for a column
I'm dealing with a Postgres table (called "lives") that contains records with columns for time_stamp, usr_id, transaction_id, and lives_remaining. I need a query that will give me the most recent lives_remaining total for each usr_id
...
Which SQL query is faster? Filter on Join criteria or Where clause?
...LEFT JOIN.
In your very case this will look like this:
SELECT *
FROM TableA a
LEFT JOIN
TableXRef x
ON x.TableAID = a.ID
AND a.ID = 1
LEFT JOIN
TableB b
ON x.TableBID = b.ID
or this:
SELECT *
FROM TableA a
LEFT JOIN
TableXRef x
ON x.TableAI...
How Do I Get the Query Builder to Output Its Raw SQL Query as a String?
...
Use the toSql() method on a QueryBuilder instance.
DB::table('users')->toSql() would return:
select * from `users`
This is easier than wiring up an event listener, and also lets you check what the query will actually look like at any point while you're building it.
...
Make body have 100% of the browser height
...the best solution:
html {
width: 100%;
height: 100%;
display: table;
}
body {
width: 100%;
display: table-cell;
}
html, body {
margin: 0px;
padding: 0px;
}
It is dynamic in that the html and the body elements will expand automatically if their contents overflow. I t...