sql - CONCAT'ing NULL fields - Stack Overflow
just run SET CONCAT_NULL_YIELDS_NULL OFF and then all null concatenations will result in text and not null..
SQL using If Not Null on a Concatenation - Stack Overflow
Since a NULL concatenated with a string yields a NULL, we can attempt to build our sub-string and replace a NULL with an empty string, which is then concatenated to the next part of the name. This assumes that FirstName and Surname are always NOT NULL, but you could apply the same logic to...
group concat - MySQL GROUP_CONCAT with Nulls - Stack Overflow
userId, questionId, selectionId 7, 3, NULL 7, 4, 1 7, 5, 2. When I query on the selection table with GROUP_CONCAT, I get the following
Using UNION SELECT Error Based
UniOn Select 1,2,3,4,...,gRoUp_cOncaT(0x7c,data,0x7C)+fRoM+... Extract columns name without information_schema. Method for MySQL >= 4.1.
mysql - Return 0 when SELECT COUNT is null - Stack Overflow
SELECT m.id, m.name, m.description, m.directions, COUNT(j.markerid) as marker_jingles FROM markers AS m LEFT OUTER JOIN jingles AS j ON j.markerid=m.id WHERE 1. But am a bit stuck because I cannot figure out how to get it to return rows when the COUNT is 0. Sincere thanks for the...
sql - COUNT(*) Includes Null Values? - Stack Overflow
This includes NULL values and duplicates. How can you have a null value in a group?
Шпаргалка по SQL инъекциям | DefconRU
(M): SELECT CONCAT(login, password) FROM members. 7. Строки без кавычек Есть несколько способов не использовать кавычки в запросе, например с помощью CHAR() (MS) и CONCAT() (M). Синтаксис: SELECT 0x457578 (M). В MySQL есть простой способ представления строки в...
sql - Counting null values as unique value - Stack Overflow
Hours 1 1 2 null null null. The result must be: 3. My query is: select count(distinct hour) from hours; but it returns: 2. I tested also
sql injection "union select null" - CodeProject
Union select null, null, null, null, null, null, null from information_schema.tables. for a small database containing three tables. this instruction is used in sql injection I tried it and it worked but I didn't really know how it works can somebody help me...
SQL запросы быстро. Часть 1 / Хабр | SELECT, FROM
SELECT, FROM — обязательные элементы запроса, которые определяют выбранные столбцы, их порядок и источник данных.