{"id":100,"date":"2018-04-11T22:12:14","date_gmt":"2018-04-11T15:12:14","guid":{"rendered":"http:\/\/www.sqlservertutorial.net\/?page_id=100"},"modified":"2024-07-29T21:50:13","modified_gmt":"2024-07-29T14:50:13","slug":"sql-server-basics","status":"publish","type":"page","link":"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/","title":{"rendered":"SQL Server Basics"},"content":{"rendered":"\n<div class=\"wp-block-group\"><div class=\"wp-block-group__inner-container is-layout-flow wp-block-group-is-layout-flow\">\n<h2 class=\"wp-block-heading\" id='querying-data'>Section 1. Querying data <a href=\"#querying-data\" class=\"anchor\" id=\"querying-data\" title=\"Anchor for Section 1. Querying data\">#<\/a><\/h2>\n\n\n\n<p>This section teaches you how to query data from an SQL Server database. We\u2019ll begin with a simple query that retrieves data from a single table.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-select\/\">SELECT<\/a>&nbsp;\u2013 show you how to query data against a single table.<\/li>\n<\/ul>\n<\/div><\/div>\n\n\n\n<div class=\"wp-block-group\"><div class=\"wp-block-group__inner-container is-layout-flow wp-block-group-is-layout-flow\">\n<h2 class=\"wp-block-heading\" id='sorting-data'>Section 2. Sorting data <a href=\"#sorting-data\" class=\"anchor\" id=\"sorting-data\" title=\"Anchor for Section 2. Sorting data\">#<\/a><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-order-by\/\">ORDER BY<\/a>&nbsp;\u2013 sort the result set based on values in a specified list of columns<\/li>\n<\/ul>\n<\/div><\/div>\n\n\n\n<div class=\"wp-block-group\"><div class=\"wp-block-group__inner-container is-layout-flow wp-block-group-is-layout-flow\">\n<h2 class=\"wp-block-heading\" id='limiting-rows'>Section 3. Limiting rows <a href=\"#limiting-rows\" class=\"anchor\" id=\"limiting-rows\" title=\"Anchor for Section 3. Limiting rows\">#<\/a><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-offset-fetch\/\">OFFSET FETCH<\/a> &#8211; limit the number of rows returned by a query.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-select-top\/\">SELECT TOP<\/a> &#8211; limit the number of rows or percentage of rows returned in a query&#8217;s result set.<\/li>\n<\/ul>\n<\/div><\/div>\n\n\n\n<div class=\"wp-block-group\"><div class=\"wp-block-group__inner-container is-layout-flow wp-block-group-is-layout-flow\">\n<h2 class=\"wp-block-heading\" id='filtering-data'>Section 4. Filtering data <a href=\"#filtering-data\" class=\"anchor\" id=\"filtering-data\" title=\"Anchor for Section 4. Filtering data\">#<\/a><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-select-distinct\/\">DISTINCT<\/a> &nbsp;&#8211; select distinct values in one or more columns of a table.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-where\/\">WHERE<\/a>&nbsp;\u2013 filter rows in the output of a query based on one or more conditions.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-and\/\">AND<\/a>&nbsp;\u2013 combine two Boolean expressions and return true if all expressions are true.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-or\/\">OR<\/a>\u2013 \u00a0combine two Boolean expressions and return true if either of the conditions is true.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-in\/\">IN<\/a>&nbsp;\u2013 check whether a value matches any value in a list or a subquery.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-between\/\">BETWEEN<\/a>&nbsp;\u2013 test if a value is between a range of values.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-like\/\">LIKE<\/a> &nbsp;\u2013&nbsp; check if a character string matches a specified pattern.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-alias\/\">Column &amp; table aliases<\/a> &#8211; show you how to use column aliases to change the heading of the query output and table aliases to improve the readability of a query.<\/li>\n<\/ul>\n<\/div><\/div>\n\n\n\n<div class=\"wp-block-group\"><div class=\"wp-block-group__inner-container is-layout-flow wp-block-group-is-layout-flow\">\n<h2 class=\"wp-block-heading\" id='joining-tables'>Section 5. Joining tables <a href=\"#joining-tables\" class=\"anchor\" id=\"joining-tables\" title=\"Anchor for Section 5. Joining tables\">#<\/a><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-joins\/\">Joins<\/a> &#8211; give you a brief overview of joins types in SQL Server including inner join, left join, right join, and full outer join.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-inner-join\/\">INNER JOIN<\/a>&nbsp;\u2013 select rows from a table that have matching rows in another table.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-left-join\/\">LEFT JOIN<\/a>&nbsp;\u2013 return all rows from the left table and matching rows from the right table. If the right table does not have corresponding rows, use NULL for the column values from the right table.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-right-join\/\">RIGHT JOIN<\/a> &#8211; learn a reversed version of the left join.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-full-outer-join\/\">FULL OUTER JOIN<\/a> &#8211; return matching rows from both left and right tables and rows from each side if no matching rows exist.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-cross-join\/\">CROSS JOIN<\/a>&nbsp;\u2013 join multiple unrelated tables and create Cartesian products of rows in the joined tables.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-self-join\/\">Self join<\/a>&nbsp;\u2013 show you how to use the&nbsp;self-join to query hierarchical data and compare rows within the same table.<\/li>\n<\/ul>\n<\/div><\/div>\n\n\n\n<div class=\"wp-block-group\"><div class=\"wp-block-group__inner-container is-layout-flow wp-block-group-is-layout-flow\">\n<h2 class=\"wp-block-heading\" id='grouping-data'>Section 6. Grouping data <a href=\"#grouping-data\" class=\"anchor\" id=\"grouping-data\" title=\"Anchor for Section 6. Grouping data\">#<\/a><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-group-by\/\">GROUP BY<\/a>\u2013 group the query result based on the values in a specified list of column expressions.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-having\/\">HAVING<\/a> \u2013 specify a search condition for a group or an aggregate.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-grouping-sets\/\">GROUPING SETS<\/a> &#8211; generates multiple grouping sets.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-cube\/\">CUBE<\/a> &#8211; generate grouping sets with all combinations of the dimension columns.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-rollup\/\">ROLLUP<\/a> &#8211; generate grouping sets with an assumption of the hierarchy between input columns.<\/li>\n<\/ul>\n<\/div><\/div>\n\n\n\n<div class=\"wp-block-group\"><div class=\"wp-block-group__inner-container is-layout-flow wp-block-group-is-layout-flow\">\n<h2 class=\"wp-block-heading\" id='section-7-subquery'>&nbsp;Section 7. Subquery <a href=\"#section-7-subquery\" class=\"anchor\" id=\"section-7-subquery\" title=\"Anchor for &nbsp;Section 7. Subquery\">#<\/a><\/h2>\n\n\n\n<p>This section covers subqueries, which are queries nested within another statement, such as SELECT, INSERT, UPDATE, or DELETE.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-subquery\/\">Subquery<\/a>\u00a0\u2013 explain the subquery concept and show you how to use various subquery types to select data.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-correlated-subquery\/\">Correlated subquery<\/a> &#8211; introduce you to the correlated subquery concept.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-exists\/\">EXISTS<\/a>&nbsp;&#8211; test for the existence of rows returned by a subquery.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-any\/\">ANY<\/a> &#8211; compare a value with a single-column set of values returned by a subquery and return TRUE if the value matches any value in the set.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-all\/\">ALL<\/a> &#8211;\u00a0compare a value with a single-column set of values returned by a subquery and return TRUE if the value matches all values in the set.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-cross-apply\/\">CROSS APPLY<\/a> &#8211; perform an inner join of a table with a table-valued function or a correlated subquery.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-outer-apply\/\">OUTER APPLY<\/a> &#8211; perform a left join of a table with a table-valued function or a correlated subquery.<\/li>\n<\/ul>\n<\/div><\/div>\n\n\n\n<div class=\"wp-block-group\"><div class=\"wp-block-group__inner-container is-layout-flow wp-block-group-is-layout-flow\">\n<h2 class=\"wp-block-heading\" id='set-operators'>Section 8. Set Operators <a href=\"#set-operators\" class=\"anchor\" id=\"set-operators\" title=\"Anchor for Section 8. Set Operators\">#<\/a><\/h2>\n\n\n\n<p>This section guides you through the steps of using set operators, including union, intersect, and except, to combine multiple result sets from input queries.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-union\/\">UNION<\/a> \u2013 combine the result sets of two or more queries into a single result set.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-intersect\/\">INTERSECT<\/a> &#8211; return the intersection of the result sets of two or more queries.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-except\/\">EXCEPT<\/a> &#8211; find the difference between the two result sets of two input queries.<\/li>\n<\/ul>\n<\/div><\/div>\n\n\n\n<div class=\"wp-block-group\"><div class=\"wp-block-group__inner-container is-layout-flow wp-block-group-is-layout-flow\">\n<h2 class=\"wp-block-heading\" id='common-table-expression-cte'>Section 9. Common Table Expression (CTE) <a href=\"#common-table-expression-cte\" class=\"anchor\" id=\"common-table-expression-cte\" title=\"Anchor for Section 9. Common Table Expression (CTE)\">#<\/a><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-cte\/\">CTE<\/a> &#8211; use common table expressions to make complex queries more readable.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-recursive-cte\/\">Recursive CTE<\/a> &#8211; query hierarchical data using recursive CTE.<\/li>\n<\/ul>\n<\/div><\/div>\n\n\n\n<div class=\"wp-block-group\"><div class=\"wp-block-group__inner-container is-layout-flow wp-block-group-is-layout-flow\">\n<h2 class=\"wp-block-heading\" id='pivot'>Section 10. Pivot <a href=\"#pivot\" class=\"anchor\" id=\"pivot\" title=\"Anchor for Section 10. Pivot\">#<\/a><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-pivot\/\">PIVOT<\/a> &#8211; convert rows to columns<\/li>\n<\/ul>\n<\/div><\/div>\n\n\n\n<div class=\"wp-block-group\"><div class=\"wp-block-group__inner-container is-layout-flow wp-block-group-is-layout-flow\">\n<h2 class=\"wp-block-heading\" id='modifying-data'>Section 11. Modifying data <a href=\"#modifying-data\" class=\"anchor\" id=\"modifying-data\" title=\"Anchor for Section 11. Modifying data\">#<\/a><\/h2>\n\n\n\n<p>In this section, you will learn how to modify data in the database using Data Manipulation Language (DML), which includes SQL commands such as INSERT, DELETE, and UPDATE.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-insert\/\">INSERT<\/a>&nbsp;\u2013 insert a row into a table<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-insert-multiple-rows\/\">INSERT multiple rows<\/a> &#8211; insert multiple rows into a table using a single INSERT statement<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-insert-into-select\/\">INSERT INTO SELECT<\/a> &#8211; insert data that comes from the result set of a query into a table.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-update\/\">UPDATE<\/a>&nbsp;\u2013 change the existing values in a table.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-update-join\/\">UPDATE JOIN<\/a> &#8211; update values in a table based on values from another table using JOIN clauses.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-delete\/\">DELETE<\/a>&nbsp;\u2013 delete one or more rows of a table.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-merge\/\">MERGE<\/a> &#8211; walk you through the steps of performing a mixture of insertion, update, and deletion using a single statement.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-transaction\/\">Transaction<\/a> &#8211; show you how to start a transaction explicitly using the BEGIN TRANSACTION, COMMIT, and ROLLBACK statements<\/li>\n<\/ul>\n<\/div><\/div>\n\n\n\n<div class=\"wp-block-group\"><div class=\"wp-block-group__inner-container is-layout-flow wp-block-group-is-layout-flow\">\n<h2 class=\"wp-block-heading\" id='data-definition'>Section 12. Data definition <a href=\"#data-definition\" class=\"anchor\" id=\"data-definition\" title=\"Anchor for Section 12. Data definition\">#<\/a><\/h2>\n\n\n\n<p>This section shows you how to manage the most important database objects including databases and tables.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-create-database\/\">CREATE DATABASE<\/a> &#8211; show you how to create a new database in an SQL Server instance using the CREATE DATABASE statement and SQL Server Management Studio.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-drop-database\/\">DROP DATABASE<\/a> &#8211; learn how to delete existing databases.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-create-schema\/\">CREATE SCHEMA<\/a> &#8211; describe how to create a new schema in a database.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-alter-schema\/\">ALTER SCHEMA<\/a> &#8211; show how to transfer a securable from one schema to another within the same database.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-drop-schema\/\">DROP SCHEMA<\/a> &#8211; learn how to delete a schema from a database.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-create-table\/\">CREATE TABLE<\/a>\u00a0\u2013 walk you through the steps of creating a new table in a specific schema of a database.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-identity\/\">Identity column<\/a> &#8211; learn how to use the IDENTITY property to create the identity column for a table.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-sequence\/\">Sequence<\/a> &#8211; describe how to generate a sequence of numeric values based on a specification.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-alter-table-add-column\/\">ALTER TABLE ADD column<\/a> &#8211; show you how to add one or more columns to an existing table<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-alter-table-alter-column\/\">ALTER TABLE ALTER COLUMN<\/a> &#8211; show you how to change the definition of existing columns in a table.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-alter-table-drop-column\/\">ALTER TABLE DROP COLUMN<\/a> &#8211; learn how to drop one or more columns from a table.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-computed-columns\/\">Computed columns<\/a> &#8211; how to use the computed columns to reuse the calculation logic in multiple queries.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-drop-table\/\">DROP TABLE<\/a>&nbsp;\u2013 show you how to delete tables from the database.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-truncate-table\/\">TRUNCATE TABLE<\/a>&nbsp;\u2013 delete all data from a table faster and more efficiently.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-select-into\/\">SELECT INTO<\/a> &#8211; learn how to create a table and insert data from a query into it.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-rename-table\/\">Rename a table<\/a>&nbsp;\u2013 &nbsp;walk you through the process of renaming a table to a new one.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-temporary-tables\/\">Temporary tables<\/a> &#8211; introduce you to the temporary tables for storing temporary immediate data in stored procedures or database sessions.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-synonym\/\">Synonym<\/a> &#8211; explain the synonym and show you how to create synonyms for database objects.<\/li>\n<\/ul>\n<\/div><\/div>\n\n\n\n<div class=\"wp-block-group\"><div class=\"wp-block-group__inner-container is-layout-flow wp-block-group-is-layout-flow\">\n<h2 class=\"wp-block-heading\" id='sql-server-data-types'>Section 13. SQL Server Data Types <a href=\"#sql-server-data-types\" class=\"anchor\" id=\"sql-server-data-types\" title=\"Anchor for Section 13. SQL Server Data Types\">#<\/a><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-data-types\/\">SQL Server data types<\/a>&nbsp;\u2013 give you an overview of the built-in SQL Server data types.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-bit\/\">BIT<\/a> &#8211; store bit data i.e., 0, 1, or NULL in the database with the BIT data type.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-int\/\">INT<\/a> &#8211; learn about various integer types in SQL server including BIGINT, INT, SMALLINT, and TINYINT.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-decimal\/\">DECIMAL<\/a> &#8211; show you how to store exact numeric values in the database by using DECIMAL or NUMERIC data type.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-char\/\">CHAR<\/a> &#8211; learn how to store fixed-length, non-Unicode character strings in the database.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-nchar\/\">NCHAR<\/a> &#8211;\u00a0 show you how to store fixed-length, Unicode character strings and explains the differences between <code>CHAR<\/code> and <code>NCHAR<\/code> data types<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-varchar\/\">VARCHAR<\/a> &#8211; store variable-length, non-Unicode string data in the database.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-nvarchar\/\">NVARCHAR<\/a> &#8211; learn how to store variable-length, Unicode string data in a table and understand the main differences between VARCHAR and NVARCHAR.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-datetime2\/\">DATETIME2<\/a> &#8211; illustrate how to store both date and time data in a database.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-date\/\">DATE<\/a>&nbsp;\u2013&nbsp;discuss the date data type and how to store the dates in the table.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-time\/\">TIME<\/a> &#8211; show you how to store time data in the database by using the TIME data type.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-datetimeoffset\/\">DATETIMEOFFSET<\/a> &#8211; show you how to manipulate datetime with the time zone.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-guid\/\">GUID<\/a> &#8211; learn about the GUID and how to use the NEWID() function to generate GUID values.<\/li>\n<\/ul>\n<\/div><\/div>\n\n\n\n<div class=\"wp-block-group\"><div class=\"wp-block-group__inner-container is-layout-flow wp-block-group-is-layout-flow\">\n<h2 class=\"wp-block-heading\" id='constraints'>Section 14. Constraints <a href=\"#constraints\" class=\"anchor\" id=\"constraints\" title=\"Anchor for Section 14. Constraints\">#<\/a><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-primary-key\/\">Primary key<\/a> \u00a0\u2013 explain the primary key concept and show you how to use the primary key constraint to manage the primary key of a table.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-foreign-key\/\">Foreign key<\/a> \u2013 introduce you to the foreign key concept and show you use the <code>FOREIGN KEY<\/code> constraint to enforce the link of data in two tables.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-not-null-constraint\/\">NOT NULL constraint<\/a> &#8211; show you how to ensure a column does not accept NULL.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-unique-constraint\/\">UNIQUE constraint<\/a>&nbsp;&#8211; ensure that data contained in a column, or a group of columns, is unique among rows in a table.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-check-constraint\/\">CHECK constraint<\/a> \u2013 walk you through the process of adding logic for checking data before storing them in tables.<\/li>\n<\/ul>\n<\/div><\/div>\n\n\n\n<div class=\"wp-block-group\"><div class=\"wp-block-group__inner-container is-layout-flow wp-block-group-is-layout-flow\">\n<h2 class=\"wp-block-heading\" id='expressions'>Section 15. Expressions <a href=\"#expressions\" class=\"anchor\" id=\"expressions\" title=\"Anchor for Section 15. Expressions\">#<\/a><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-case\/\">CASE<\/a> &#8211; add if-else logic to SQL queries by using simple and searched CASE expressions.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-coalesce\/\">COALESCE<\/a> &#8211; handle NULL values effectively using the COALESCE expression.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-nullif\/\">NULLIF<\/a> &#8211; return NULL if the two arguments are equal; otherwise, return the first argument.<\/li>\n<\/ul>\n<\/div><\/div>\n\n\n\n<div class=\"wp-block-group\"><div class=\"wp-block-group__inner-container is-layout-flow wp-block-group-is-layout-flow\">\n<h2 class=\"wp-block-heading\" id='useful-tips'>Section 16. Useful Tips <a href=\"#useful-tips\" class=\"anchor\" id=\"useful-tips\" title=\"Anchor for Section 16. Useful Tips\">#<\/a><\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/sql-server-find-duplicates\/\">Find duplicates<\/a> &#8211; show you how to find duplicate values in one or more columns of a table.<\/li>\n\n\n\n<li><a href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/delete-duplicates-sql-server\/\">Delete duplicates<\/a> &#8211; describe how to remove duplicate rows from a table.<\/li>\n<\/ul>\n<\/div><\/div>\n","protected":false},"excerpt":{"rendered":"<p>The SQL server basics section shows you how to use the Transact-SQL (T-SQL) to interact with SQL Server databases.  You will learn how to manipulate data from the database such as querying, inserting, updating, and deleting data.<\/p>\n","protected":false},"author":1,"featured_media":2734,"parent":0,"menu_order":2,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-100","page","type-page","status-publish","has-post-thumbnail","hentry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.5 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>SQL Server Basics<\/title>\n<meta name=\"description\" content=\"The SQL server basics section shows you how to use the Transact-SQL (T-SQL) statements to interact with SQL Server databases.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.sqlservertutorial.net\/sql-server-basics\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta 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