Frequent question: How do I count records from two tables in SQL?

How do I count records in two tables in SQL?

To achieve this for multiple tables, use the UNION ALL. select sum(variableName. aliasName) from ( select count(*) as yourAliasName from yourTableName1 UNION ALL select count(*) as yourAliasName from yourTableName2 ) yourVariableName; Let us implement the above syntax.

How do you SELECT data from two tables in SQL?

Different Types of SQL JOINs

  1. (INNER) JOIN : Returns records that have matching values in both tables.
  2. LEFT (OUTER) JOIN : Returns all records from the left table, and the matched records from the right table.
  3. RIGHT (OUTER) JOIN : Returns all records from the right table, and the matched records from the left table.

How do you SELECT common records from two tables?

7 Answers. If you are using SQL Server 2005, then you can use Intersect Key word, which gives you common records. If you want in the output both column1 and column2 from table1 which has common columns1 in both tables. Yes, INNER JOIN will work.

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How can I get data from multiple tables?

In SQL, to fetch data from multiple tables, the join operator is used. The join operator adds or removes rows in the virtual table that is used by SQL server to process data before the other steps of the query consume the data.

How do I count total records in SQL?

SQL COUNT() Function

  1. SQL COUNT(column_name) Syntax. The COUNT(column_name) function returns the number of values (NULL values will not be counted) of the specified column: …
  2. SQL COUNT(*) Syntax. The COUNT(*) function returns the number of records in a table: …
  3. SQL COUNT(DISTINCT column_name) Syntax.

How do I count tables in SQL database?

INFORMATION_SCHEMA. TABLES returns one row for each table in the current database for which the current user has permissions. As of SQL Server 2008, you can also use sys. tables to count the the number of tables.

How do I count duplicate rows?

Tip: If you want to count the duplicates in the whole Column, use this formula =COUNTIF(A:A, A2) (the Column A indicates column of data, and A2 stands the cell you want to count the frequency, you can change them as you need).

How can I fetch data from two tables in mysql without joining?

User-271186128 posted

  1. Create a temporary table (include table 1 and table 2 columns).
  2. Query the matched records from table 1 and table2, and insert them into the temporary table.
  3. Query the not matched records from table 1, and insert it into the temporary table.
  4. Query the temporary table. Get the required value.

How do you fetch data that is common in two query results?

The SQL INTERSECT operator is used to combine like rows from two queries. It returns rows that are in common between both results. To use the SQL INTERSECT operator, both queries must return the same number of columns and those columns must be of compatible data types.

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What is difference between inner join and intersect?

They are very different, even in your case. The INNER JOIN will return duplicates, if id is duplicated in either table. INTERSECT removes duplicates. The INNER JOIN will never return NULL , but INTERSECT will return NULL .

How does intersect work in SQL?

The INTERSECT clause in SQL is used to combine two SELECT statements but the dataset returned by the INTERSECT statement will be the intersection of the data-sets of the two SELECT statements. In simple words, the INTERSECT statement will return only those rows which will be common to both of the SELECT statements.

How can I get data from two tables in a single query?

From multiple tables

To retrieve information from more than one table, you need to join those tables together. This can be done using JOIN methods, or you can use a second SELECT statement inside your main SELECT query—a subquery.

How do I join two tables without joins in SQL?

One way to join two tables without a common column is to use an obsolete syntax for joining tables. With this syntax, we simply list the tables that we want to join in the FROM clause then use a WHERE clause to add joining conditions if necessary.

How do I inner join multiple tables in SQL?

The following illustrates INNER JOIN syntax for joining two tables:

  1. SELECT column1, column2 FROM table_1 INNER JOIN table_2 ON join_condition;
  2. SELECT productID, productName, categoryName FROM products INNER JOIN categories ON categories.categoryID = products.categoryID;
  3. categories.categoryID = products.categoryID.