SELECT N Percent of Records in MySQL

The ability to select a certain percentage of records from a query or database table can be important when working with lots of data. Luckily this is easy to do in MySQL with the RAND() function and a WHERE clause. RAND() returns a random floating point number between 0 and 1, making it easy to

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How to Select a Random Sample of Records in MySQL

The ability to select a random sample of records from query or database table can be important when working with lots of data. Luckily this is easy to do in MySQL with the RAND() function and a WHERE clause. RAND() returns a random floating point value between 0 and 1, making it very easy to

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How to Left Pad Numbers in AWK

Occasionally when working in a Linux/Unix environment comes the need to left pad numbers with zeros (add leading zeros to numbers). This is often done to make a series of numbers the same length. An example of doing this with awk can be seen below:

How to Stop all Running Docker Containers

People that work with Docker know it is easy to create a large number of containers. Occasionally you need to stop all running containers on your machine. This can be accomplished by using docker stop together with docker ps (using command substitution).

docker ps is used to list all running containers. The -q option

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How to Merge multiple commits in Git

The ability to merge multiple commits in Git is a huge plus. Merging commits requires “rebasing” which will essentially rewrite the project history appending commits onto the last commit (by default) in a different branch, or even to an earlier commit in the same branch. Rebasing can have some damaging effects, so be careful when

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Counting Relationships in Neo4j

When working with different graphs in Neo4j, it is often important to count the number of relationships between different nodes. Below are examples of common relationship counting tasks. The data for these examples can be found here and the script to load this data into Neo4j can be found here. Counting Total Relationships (Edges) MATCH

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Delete all Nodes and Relationships in a Neo4j Database

Deleting Nodes and Relationships Deleting all nodes and relationships in a Neo4j database is very simple. Here is an example that does just that: MATCH (n) DETACH DELETE n; The DETACH keyword specifies to remove or “detach” all relationships from a particular node before deletion. If relationships exist on a node at the time deletion

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Load a Tab Delimited File into Neo4j

Neo4j is a popular graph database which provides an easy way to import text files using the Cypher query language and a LOAD CSV clause. LOAD CSV by default expects files to be delimited by commas. In order to specify another field delimiter, add FIELDTERMINATOR to the LOAD CSV clause. For example:

The statement

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Running Neo4j 3.x on Docker

Neo4j is the world’s leading graph database. Fortunately, Neo Technology publishes official Neo4j Docker images which makes it very easy to get started. Once you have Docker running, simply use the the following command to start running Neo4j in a new container (adjust Neo4j version as necessary):

The -p (or –publish) options above binds

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Sorting JSON by Value with JQ (Command Line JSON Processor)

jq is a lightweight command line JSON processor that is very easy to use. Sometimes it is helpful to see your data sorted by a particular field value. Luckily jq makes this easy to do. Here are some sample JSON records we will be working with in this post:

Sorting JSON by value with

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