SQL Chwazi Deklarasyon

SELECT se deklarasyon nan SQL itilize rekipere done ki sòti nan yon tab baz done.

Nou ka itilize SELECT deklarasyon yo ka resevwa done ki sòti nan kolòn nan espesifye (yo) oswa tout kolòn yo.



SQL CHWAZI sentaks

SELECT deklarasyon gen sentaks sa a:


SELECT column1, column2, ... FROM table_name;

Egzanp Deklarasyon SQL SELECT

Sipoze nou gen yon tab ki rele 'Anplwaye' ak done sa yo:

+------------+-----------+----------+------------+ | EmployeeID | FirstName | LastName | Department | +------------+-----------+----------+------------+ | 1

| Mark
| Otto
| Finance | | 2

| Jacob
| Thornton | IT
| | 3

| Su
| Bird
| Marketing | | 4

| Sam
| Burger | IT
| +------------+-----------+----------+------------+


CHWAZI Soti nan yon kolòn

Pou chwazi kolòn 'Depatman' nan tablo 'Anplwaye yo':


SELECT Department FROM Employees;

Sòti:

+------------+ | Department | +------------+ | Finance | | IT
| | Marketing | | IT
| +------------+


CHWAZI Soti nan kolòn miltip

Pou chwazi 'Depatman' ak 'EmployeeID' kolòn nan tablo a 'Anplwaye':

SELECT EmployeeID, Department FROM Employees;

Sòti:

+------------+------------+ | EmployeeID | Department | +------------+------------+ | 1

| Finance | | 2

| IT
| | 3

| Marketing | | 4

| IT
| +------------+------------+


CHWAZI * Deklarasyon

Pou chwazi tout kolòn ki nan tablo 'Anplwaye yo':


SELECT * FROM Employees;

Sòti:

+------------+-----------+----------+------------+ | EmployeeID | FirstName | LastName | Department | +------------+-----------+----------+------------+ | 1

| Mark
| Otto
| Finance | | 2

| Jacob
| Thornton | IT
| | 3

| Su
| Bird
| Marketing | | 4

| Sam
| Burger | IT
| +------------+-----------+----------+------------+


Rezilta Filter Sèvi ak KI KOTE Clause

Nou ka filtre rezilta yo nan yon SELECT rechèch lè l sèvi avèk WHERE kloz.

Pou egzanp, yo chwazi tout anplwaye nan 'IT Depatman an' itilize:

SELECT * FROM Employees WHERE Department='IT'

Sòti:


+------------+-----------+----------+------------+ | EmployeeID | FirstName | LastName | Department | +------------+-----------+----------+------------+ | 2

| Jacob
| Thornton | IT
| | 4

| Sam
| Burger | IT
| +------------+-----------+----------+------------+

Menm jan an tou, yo chwazi tout Id anplwaye ki nan 'IT Depatman an' nou itilize:

SELECT EmployeeID FROM Employees WHERE Department='IT'

Sòti:

+------------+ | EmployeeID | +------------+ | 2

| | 4

| +------------+