sql count
/*COUNT(column_name) will return the number of rows from the column
that are not NULL*/
SELECT COUNT(column_name)
FROM table_name;
/*COUNT(*) will return the number of rows from the table*/
SELECT COUNT(*)
FROM table_name;
sql count
/*COUNT(column_name) will return the number of rows from the column
that are not NULL*/
SELECT COUNT(column_name)
FROM table_name;
/*COUNT(*) will return the number of rows from the table*/
SELECT COUNT(*)
FROM table_name;
how to join tables in sql
JOINING 2 Tables in sql
SELECT X.Column_Name , Y.Column_Name2
FROM TABLES1_NAME X
INNER JOIN TABLES2_NAME Y ON X.Primary_key = Y.Foreign_key;
--FOR EXAMPLE
--GET THE FIRST_NAME AND JOB_TITLE
--USE EMPLOYEES AND JOBS TABLE
--THE RELATIONSHIP IS JOB_ID
SELECT E.FIRST_NAME , J.JOB_TITLE
FROM EMPLOYEES E
INNER JOIN JOBS J ON J.JOB_ID = E.JOB_ID;
how to count number of rows in sql
SELECT COUNT(*)
FROM dbo.bigTransactionHistory;
sql count(*)
SELECT COUNT(column_name)
FROM table_name
WHERE condition;
sql join
-- Rows with ID existing in both a, b and c
-- JOIN is equivalent to INNER JOIN
SELECT a.ID, a.NAME, b.VALUE1, c.VALUE1 FROM table1 a
JOIN table2 b ON a.ID = b.ID
JOIN table3 c ON a.ID = c.ID
WHERE a.ID >= 1000;
-- ⇓ Test it ⇓ (Fiddle source link)
count sql
SELECT COUNT(column_name)
FROM table_name
WHERE condition;
--Return number of rows
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