sql query with nolock

the table vertically and horizontally to reduce the table size (sp_spaceuse) 3) upgrade hardware 4) Create an index based on the query conditions, optimize the index, optimize the access mode, and limit the data volume of the result set. Note that the fill factor should be appropriate (preferably the default value 0 ). The index should be as small as possible. Use a column with a small number of bytes to create an index (refer to the index creati

First, we will compare two paging SQL statements. For example, the news table has 0.15 million records, NewsTypeId10 has 90 thousand records, and NewsTypeID10 is currently queried. Which SQL statement will be considered as highly efficient? First, compare the two paging SQL statements. Assume that the news table has 0.15 million records, NewsTypeId = 10 has 90 th

Routine collection of commonly used SQL query statements and SQL statements Common SQL query statements are as follows: 1. Simple query statements 1. view the table structure SQL> DESC

T-SQL dynamic query (1) -- Introduction Preface: During feature development, we often encounter a scenario similar to the following: the application has a query function that allows users to select the required conditions among many query conditions. This is also the focus of this series. But sometimes you may find

the cursor. Optimistic read-only value When nolock is specified, the table with the specified prompt is read-only in the cursor. 16. Use profiler to track the query, obtain the time required for the query, and locate the SQL problem. Use the index optimizer to optimize the index. 17. Pay attention to the difference be

SQL, Structured query Language Structured Query Language , is a database query and programming language for accessing data and querying, updating, and managing relational database systems. SQL language contains 4 sections:※ data definition language (DDL) create ,

ThinkPHP -- SQL query statement, ThinkPHP -- SQL statement I. Query Method ThinkPHP provides three basic query methods: String condition query, Index Array condition query, and object b

), variable length, can hold photos, files, etc. int, integer field. Example: Userage int float, floating-point data is approximate. Example: Userresults float, the approximate numeric data type used to represent floating-point numeric data. datetime, Date type. Example: Createdatetime datetime Bit, Boolean type. Can be set to True is male, false is schoolgirl If the content is very much, indeterminate length (such as article), can be used: nvarchar (max) 6. Save the tabl

Steps for Oracle to execute SQL query statements and oraclesql query statements Steps for Oracle to execute SQL query statements If you enter the following query statement in SQL * Plus

Optimization of SQL massive data query and non-use like processing solutions, data query like 1. To optimize the query, try to avoid full table scanning. First, consider creating an index on the columns involved in where and order. 2. Try to avoid null value determination on the field in the where clause. Otherwise, th

Optimization of SQL massive data query and non-use like processing solutions, data query like 1. To optimize the query, try to avoid full table scanning. First, consider creating an index on the columns involved in where and order.2. Try to avoid null value determination on the field in the where clause. Otherwise, the

How can I convert Oracle queries to queries in the SQL database? The following describes how to convert an Oracle query to an SQL query. If you are interested in Oracle query, take a look. Oracle's TO_CHAR function can convert the n-bit NUMBER data type to the VARCHAR2 data

SQL query beginner's Guide Reading Notes (2) Creating SQL queries, beginner's guide SQL PARTII: SQL Basics CHAPTER 4 Creating a Simple Query This section describes how to create an SQL