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SQL to find the number of distinct values in a column
...aggregate function:
SELECT COUNT(DISTINCT column_name) AS some_alias FROM table_name
This will count only the distinct values for that column.
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SQL update trigger only when column is modified
...oRepair <> I.QtyToRepair
END
END
2- Use Join between Inserted table and deleted table
ALTER TRIGGER [dbo].[tr_SCHEDULE_Modified]
ON [dbo].[SCHEDULE]
AFTER UPDATE
AS BEGIN
SET NOCOUNT ON;
UPDATE SCHEDULE
SET modified = GETDATE()
, ModifiedUser = SUSER_NAME...
Rails 4: List of available datatypes
... is not set to use :sql, then your schema.rb file wont be able to dump the table that uses types like :json. The schema will still be dumped for the tables that use default types but you'll see a comment for the table with special types like, "could not dump table...". Look here to set the schema_fo...
MySQL LIKE IN()?
...
Over 1 million rows in my table. REGEX arround 0.0009 and LIKE arround 0.0005. If more then 5 REGEX, arround 0.0012...
– David Bélanger
Nov 26 '11 at 5:24
...
Stored procedure slow when called from web, fast from Management Studio
... change:
ALTER PROCEDURE [dbo].[sproc]
@param1 int,
AS
SELECT * FROM Table WHERE ID = @param1
to:
ALTER PROCEDURE [dbo].[sproc]
@param1 int,
AS
DECLARE @param1a int
SET @param1a = @param1
SELECT * FROM Table WHERE ID = @param1a
Seems strange, but it fixed my problem.
...
Disable ONLY_FULL_GROUP_BY
...For instance, insert (below the [mysqld] section) sql_mode = "STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION"
– Vincent Pazeller
Nov 22 '16 at 10:44
...
Equals(=) vs. LIKE
...rmance:
A personal example using mysql 5.5: I had an inner join between 2 tables, one of 3 million rows and one of 10 thousand rows.
When using a like on an index as below(no wildcards), it took about 30 seconds:
where login like '12345678'
using 'explain' I get:
When using an '=' on the s...
What are best practices that you use when writing Objective-C and Cocoa? [closed]
...lass? That is especially true in an environment like the iPhone.
3.5) In table cells, make every element (including the cell itself) opaque for performance. That means setting the appropriate background color in everything.
3.6) When using an NSURLConnection, as a rule you may well want to implem...
Sequelize Unknown column '*.createdAt' in 'field list'
...he error is that you have timestamps enabled in sequelize, but your actual table definitions in the DB do not contain a timestamp column.
When you do user.find it will just do SELECT user.*, which only takes the columns you actually have. But when you join, each column of the joined table will be a...
What replaces cellpadding, cellspacing, valign, and align in HTML5 tables?
...
/* cellpadding */
th, td { padding: 5px; }
/* cellspacing */
table { border-collapse: separate; border-spacing: 5px; } /* cellspacing="5" */
table { border-collapse: collapse; border-spacing: 0; } /* cellspacing="0" */
/* valign */
th, td { vertical-align: top; }
/* align (center) ...